Not entirely sure your analysis passes muster. While it is true pigs like chrome and slack are the norm, computers still have many orders of magnitude more memory than 20 years ago and even if a large GUI app keeps state on disk most of it should be hot in some kind of cache whether an explicit cache or just the OS page cache.

There are other forces at work.

For instance on my primary workstation after a period of time from cold boot, pretty much everything is sitting comfortably in 32 GB of memory. A lot of time is more due to the

1) sheer volume of crap that has to be shuttled in memory, because memory accesses still aren’t free 2) there’s a surprising amount of repetitive CPU intensive tasks just to get a program started up on merely bookkeeping tasks like linking, conversion, parsing.

In addition to all the built in latencies already mentioned.

To prove this you can setup a system using a RAM disk and notice that responsiveness is often still subpar.