I installed some old Debian versions in virtual machines recently, and had a similar thought. Other than security upgrades really 99% of anything useful was already included ~25 years ago. Could probably go back quite a bit further. One annoying thing beyond ~20 years is going back to pre-UTF-8 and having to worry about 8-bit (sometimes 7-bit) character encodings, but that is the only obvious downside. Emacs versions around version 20 also were lacking things that I use today, but nothing that I could not learn to live without.

And you can install everything. As in, you can download (from their archive) the distribution ISOs from old Debian releases. For early version everything fits on a single DVD or single CD-ROM. That is thousands of libraries and applications. You don't have to think about disk space (or RAM) when installing things from there in 2025. Also everything runs very fast.

It's like hardware has finally caught up. The level of bloat from ~2000 is perfect for 2025, especially if you want to be able to set up and run virtual machines without worrying about resource use. For offline use running applications in virtual machines it is perfect.