Whenever you have to wait for things on modern computers, you’ve essentially been robbed.
IF everything is in the cache, there is no dependency on I/O, and cycles aren't wasted with context switching between usermode->kernel.
Unless your program is purely computational it's going to burn cycles on system calls and I/O.
And almost all of the network traffic and syscalls can be mitigated almost all of the time. Eg by caching, buffered IO, cutting out bloat, minifying javascript, static rendering, using lower res assets, and so on.
There’s exceptions - AI, video games, rendering and simulations work can take real time.
But other than that, modern computers should boot instantly, and apps should open instantly. Webpages should open within about 3x the server round trip time. There is very little software I’ve ever worked with that, with some effort, couldn’t be massively optimized.
But it wasn't a simple piece of software, either. This sound recorder is.
And I'll let an expert chime in here, but I think we're many orders of magnitude faster now, on the hardware side.