A good way to reality check this is to think about how frequently we saw loading splash screens then vs now. Back then it was common. Office suites, IDEs, browsers, pretty much any non-trivial app would show you a splash screen whilst it loaded. Some even had progress bars in the splash screens. Nowadays even web apps don't have splashes (though you could argue that grey loading flashers are the modern equivalent).
A lot of that was simply down to how slow hard drives were back then. I can not overstate what a miracle of performance it is jumping from a 7200RPM (or 5400!) HD to today's solid state storage. Tens of thousands of times faster in many cases.
But if you compare data transfer speed of an IDE 33 rotating hard disk against a SATA (or better Nvme) SSD, and then, once data is transferred from storage you managed it in what amount of (much slower) RAM (at the most in 8 Mb in Win 3.x times, probably 48 or 96 Mb with win 9x, 128 or 256 Mb on NT 4.00 or 2K, while nowadays it is 4/8/16 Gb) and on a single core processor, running at 100-1000 Mhz, while nowadays you have likely minimum 4 cores runnning at 3,000 or something like that.
Sure you had splash screens, the sheer fact that you could open a spreeadsheet amd make some calculations (often with automatic calculation disabled and thus pressing F9 manually to re-calculate) was (IMHO) a miracle in Windows 3.x times.
This is a pet peeve of mine but today developers should be (only for testing their programs) be given the lowest powered machines available, connected to the same (shitty) internet connection a large part of the future users of the programs actually experience and see directly why their programs/tools/websites/whatever are laggish/slowish for their customers.
Many web pages have loading progress bars. They're usually only 1-2 pixels thick and take up the entire top 1-2 rows of pixels on the page. Some stuff loads asynchronously, so it can be easy to miss them, but I see them all the time. Just today, I was using Jenkins and it does that!
I'd say it's not so big these days after SSD became the norm, but a lot of apps there for awhile would set a start up program in the system tray. That would preload most of the dlls in memory so when you ran the executable it loaded much faster.
Adobe, for example, has a ton of common libraries that load at startup.
