In a discussion about innovation in operating systems, someone on Reddit wrote "look at the electric guitar, that hasn't changed much in fifty years and you don't see people complaining."
Which got me thinking. And blathering. Appended is a somewhat rambling discourse arguing that yes, in fact, electric guitars and their related gear has changed considerably in the last fifty years. My apologies for the lack of editing; I was mostly just getting a string of ideas down.
You are correct that the biggest-name manufacturers seem mostly to be looking backwards: all the vintage reissues, replicas, etc., and even the models where they take a perfectly good guitar and destroy it to make it look like it's been played hard for 50 years. Because there seems to be the most money to be made in feeding nostalgia back to aging guitarists.
But this isn't the whole picture -- there have been some very significant developments. The Parker Fly alone has a pretty radical tremolo redesign, and that carbon fiber and fiberglass make it incredibly light (resonant, and easy on the back). That line alone has a lot of patents.
There's the Adamas graphite-top acoustic, much better protected against humidity and temperature changes than the traditional spruce top. And the Rainsong and similar models that are nearly indestructible compared to traditional acoustics that can crack just sitting in the case, because they get too dry during the winter.
Electric-acoustic pickup designs are vastly improved, to the point where I can record my Ovation without using a mic and have it sound very much like recording it with a good mic. (In fact, I recently tried this, using an Apogee Ensemble direct input compared to a Rode NT-5, and they are fairly hard to distinguish).
There's the guitar synth, the Roland VG-88, the 13-pin output becoming a semi-standard. Fender has a guitar with a built-in guitar synth.
Truss rods are becoming more usable because companies have decided that you shouldn't actually have to take the neck off to adjust the relief. There's the Peavey micro-tilt adjustment, which has made it into other brands; I think you can do the micro-tilt adjustment on some Fenders and G&L instruments now. It really helps tweak the setup.
Pickup designs are proliferating, from the G&L single coils and the somewhat oddball Alumitone pickups. Shielding and noise rejection are much improved. Bridges and nut materials are much improved.
There's the Peterson virtual strobe tuner line, with such improved accuracy that I can use it for setting intonation, something very hard to do with an ordinary tuner. I have one of these that I got used on eBay, and it has made it possible for me to set up my own guitars better than ever before. They play far more in tune.
There's the Buzz Feiten tuning system, which is proprietary and only included on particular models, but it is a huge unsung advancement in making a guitar actually play in tune in more than one key and in more than one part of the neck. And there are related products and parts and technologies.
There's the piezo bridge on electrics, now common. There are now nylon-string semi-solid-body piezo electrics that sound very cool. Godin is making an 11-string oud-tuned electric nylon "Glissentar" for Turkish oud players. That's crazy cool.
There's the whole Variax thing, where one guitar can play like a simulation of a dozen varieties, perhaps not perfectly but enough to inspire considerable creativity, and limited more by your tastes than by the technology.
There's the Chapman Stick, and a whole lot of knockoffs, with tapping and crossed-hands technique and alternate tunings. I don't own one currently but I used to, and I love to play them; they are incredibly challenging and give you a whole new palette of sounds.
There's amp modeling, whereby I can buy a cheap Roland amp that sounds really amazingly like a wide variety of tube amps (basically, solid-state amps in general sound much better than they did when I was a kid). And tube amps sound better too -- I have a 5-watt Peavey Mini Colossal tube amp that is small and reliable and sounds fantastic. It's the first tube amp I've owned despite having played guitar for 25 years.
There's the Gibson robot guitar (which I actually think is pretty dumb, but I'm sure they will sell quite a few of them).
There's even a Moog guitar.
There's a new line of decent-sounding Steinberger guitars and basses including a headless/fretless bass with an ebony bridge, carbon fiber reinforcement in the neck, and piezo pickups that sounds remarkably like an acoustic upright bass. The original Steinberger basses are now highly collectible. The new ones are so strong you can lay one between two chairs and jump on it and it won't even go out of tune. (There's a YouTube video showing this, although I'm not gonna try it on my own instrument, thanks).
There are locking tuners. There are self-locking tuners. There are self-locking tuners that cut off the excess string for you. Yes, even such a basic thing as tuning knobs have vastly improved. It's easy to forget until you go back and actually play a real vintage guitar. You can get locking tuners that are replicas of vintage tuners, to combine the old look and the new tech.
The whole CNC machining thing has existed only since the late 1970s. On the downside, it has made floods of cheap knock-offs available, but on the upside, the basic shaping is heavily automated, which makes even high-end guitars less labor-intensive; it lets the luthier put his or her energy into the finishing touches and final set-up.
Strings are better -- of better quality metals, more uniform and consistent, with coatings, more resistant to breakage. Most of the touted advances are pure marketing drivel (do I really want my strings to be cryogenically treated?) but there is no denying that electric strings with improved windings and ends break less often, and acoustic strings with the various coatings, shipped in nonreactive airtight packaging, stay less oxidized and sound brighter longer. Bass strings come in a huge variety of types now including tape-wound (easy on the fingers), half-ground, flat-wound...
Fretting materials are better. My Parker Fly and Jag-Stang with a replacement neck have stainless-steel frets. There are more varieties in fret shape and design. There's the Plek machine that can do incredibly accurate fretboard leveling, allowing lower action.
There is an absolutely bewildering variety of specially-designed tools available for luthiers. If you get the Stewart-MacDonald or "Stewmac" catalog, you know what I mean. You can even buy them as a home luthier without a true workshop and benefit from some of these great and time-saving tools.
So, actually, I think there have been significant improvements. They are just not radical and revolutionary, more stepwise. And there will always be traditionalists who want their fragile, heavy Les Pauls and Marshall stacks. But if you put did a direct comparison of, say, a vintage Les Paul and Marshall with, say, a Parker Fly Adrian Belew signature model with a rack of synth and modeling gear, you'd see that, yep, things have changed!