For most users that is true. I think there were several applications that drove the demand for more memory, then the 32bit -> 64bit transition drove it further but now for most users 16GB is plenty.
16 GB RAM is above average. I've just opened BestBuy (US, WA, and I'm not logged in so it picked some store in Seattle - YMMV), went to the "All Laptops" section (no filters of any kind) and here's what I get on the first page: 16, 8, 12, 8, 12, 4, 4, 4, 4, 8, 8, 8, 8, 16, 16, 4, 4, 8. Median value is obviously 8 and mean/average is 8.4.
I'd say that's about enough to comfortably use a browser with a few tabs on an otherwise pristine machine with nothing unusual running in background (and I'm not sure about memory requirements of all the typically prenistalled crapware). Start opening more tabs or install some apps and 8GB RAM is going to run out real quick.
And it goes as low as 4 - which is a bad joke. That's appropriate only for quite special low-memory uses (like a thin client, preferably based on a special low-resource GNU/Linux distro) or "I'll install my own RAM anyway so I don't care what comes stock" scenario.
I agree that 4 GiB is too low for browsers these days (and has been for years) but but that is only because the web is so bloated. But 4 GiB would also be a waste on any kind of thin client. Plenty of local applications should run fine on that with the appropriate OS.
