Love a machine that can just keep going.

How did mid-2000s computer users get along with just 1 GB of RAM or less?

As of today, anything less than 8 GB of RAM seems impractical. A handful of tabs in a web browser and file manager can quickly fill that up.

Shortly after booting, 2 GB of RAM are already eaten up on today's operating systems.

When I occasionally used an older laptop computer with 6 GB of RAM (because it has more ports and better repairability than today's laptops; before upgrading the memory), most of the time over 5 GB were in use, and that did not even include disk caching.

It appears that today's web browsers are far more memory-intensive than 2000s web browsers, even if we do similar things people did in the 2000s: browsing text-based pages with some photos here and there, watching videos, messaging and mailing, forum posting, and perhaps gaming. Tabbed browsing already was a thing in the 2000s. Microsoft added tabs to their pre-installed browser in 2006, back when an average personal computer had 1 GB of RAM, and an average laptop 512 MB!

Perhaps a difference is that people today watch in 720p or 1080p whereas in the 2000s, people typically watched at 240p, 360p, or 480p, but that still does not explain this massive difference. (Also, I pick a low resolution anyway when mostly listening to a video in background.)

One could create a swap file to extend system memory, though that is not healthy for an SSD in the long term. On computers, RAM is king.