Speaking of light generation... how about fluorescent lights? Those work on a fundamentally different principle than incandescents. And LEDs, which work in yet a different way? Granted, to the end user, they don't seem that different - but that's because of a large engineering effort that's been put forth to allow them to be packaged in a way that lets them easily replace incandescent lights.
Thinking about it, it seems to me that a big difference in modern innovation is backwards-compatibility. When electrical power generation and electric lighting were first being introduced, there was no installed base of any sort - before that, all power generation had been local, and only fuel was distributed. Now, though, there's a huge installed base, and new technologies need to be able to integrate into that. Thus, while the original electric light bulbs (and later on, fluorescent tubes) looked like something new, newer light bulbs don't look that different.
In the same way, when the first automobiles were introduced, there wasn't the existing infrastructure of paved roads, parking lots, etc. that we have today. Now that we have all those things, new types of automobiles have to be able to work with what we have, which limits the degree of innovation possible, and makes new cars look a lot like the old ones, even if their internal operation is fundamentally different. Electric cars are designed to look and operate like our existing gas-powered cars as much as possible - so if you're not driving one yourself, you may not even notice the growing numbers of them around.
There's also conservatism. Not the political kind - the kind that makes people say "X has worked well enough my whole life, why don't we just keep it?" Look at the resistance many people show to changing to LED and fluorescent bulbs. Yes, there are disadvantages - but there were disadvantages to switching to electrical light in general. Instead of having an oil lamp you could easily move around, you have one with a cord that had to be plugged in. And you had to have your whole house turned upside down to install all that wiring. And having all that wiring installed cost a lot. And then you had to pay money every month to the electric company. The same with cars - a good horse learned the way, but a car couldn't. And people could feed their horses from their family farm - they didn't have to go buy expensive, smelly, dangerous gasoline. And if your horse was sick, you could tell - you didn't have to worry about it suddenly dying on you halfway home for no apparent reason.
Heck, my dad doesn't use email, or have a mobile phone. Doesn't need them, he says. And he's right - he has almost seventy-five years of experience in getting along without them. From his point of view, they're more trouble than they're worth. Great for other people, who need them for something, but not for him.
People see the disadvantages in new technologies, while they've become accustomed to the disadvantages of those they're used to. Combine that with the fact that the external forms of new technologies aren't as different as they were in the past, and it's natural that people think innovation has stopped.