The long term trend is toward ever more specialization. Even a "full stacker" implies a certain subset of web tech. You wouldn't hire a "full stacker" to do your kernel work, or device driver, or likely even your mobile app. 30 years ago, programmers was programmers.
There might be a momentary tick downward on this trend, like a correction in the stock market. But I don't think it changes the overall direction, and honestly I haven't even noticed a blip.
These days knowledge work seems to be about making everyone a "fullstacker".
I love learning but I think it is more than a bit wasteful to let me do css work (I have red/green colorblindness).