Pre-internet windows 95 was fine, as long as your hardware was good. A lot of folks had off-brand CPUs with bad cooling, off-brand RAM with problems, etc. which lead to a lot of instability. But on a plain old Intel pentium with good RAM Windows 95 would run forever.
It was a hermetically sealed little environment--there were no updates or changes unless you popped a floppy disk in and made them. If you didn't do anything different it would boot up the next day just like it did the days prior. It wasn't until we started getting those machines on the internet regularly and started running a lot more background tasks, services, new software, etc. that they really started to degrade.
Before the internet was on 24/7 with broadband connections everywhere people didn't run their PC all the time. It's not like you had a local wifi network to serve data, etc. to your other devices. You turned the PC on, played a game, did some spreadsheets, dialed in to AOL, and then turned it off. Those PCs pulled 300+ watts of power at idle too and were huge power hogs. Running your windows 95 PC nonstop for days and months at a time was not common at all.
Maybe, maybe not. At the times W95 was usual, I mostly ran NetBSD and later some Gentoo and Debian on my assorted systems. Furthermore, most systems had PSUs rated at 200 to 250 Watt, which they didn't even burn if one used operating systems which knew what to do with the CPUs HLT instruction during idle, or less load, also spinning down disks was a thing.
BTW, there was software which made W95/98 use HLT too. Rain, Waterfall, CPUidle, or something like that. Which became obsolete with W2000 which did that by itself.
It was a hermetically sealed little environment--there were no updates or changes unless you popped a floppy disk in and made them. If you didn't do anything different it would boot up the next day just like it did the days prior. It wasn't until we started getting those machines on the internet regularly and started running a lot more background tasks, services, new software, etc. that they really started to degrade.