[mixmastamyk]

It’s just historical. Believe the large number of top level directories was a result of ken not having enough space on a single disk on his PDP, when that was precious.

For years I’ve been putting all user data into a separate /data partition and have kept the OS partition small (~30gb). But you have to fix the system when first installed. When I still used Windows I had the same c:/d: split.

More recently started putting kernels into a bigger ESP (EFI) partition with sdboot or uki.

With terabyte system disks, running out of space mostly doesn’t happen anymore unless you made the system partition(s) small. Don’t do that, give them plenty of GB, each of which are now thousandths of the disk.

[codedokode]

No. This makes configuration complex, pain to restore if something breaks, and some partitions will have lot of unused space.

[mixmastamyk]

Not at all. Having your data on a separate partition makes system upgrades and backups a breeze, the opposite of what you said. Only one percent of my disk is currently "wasted," and I can live with that.