It is not number of packages! 20.04 has 2977 packages and 23.10 has 1841 (from pkglist from distrowatch). After a quick eyeballing, example packages in 20.04 but NOT in 23.10: apache, g++, qemu, php, postgres, samba.

Also for comparison:

- MacOS installer ~14G [0]

- Windows 11 installer ~8G [1]

- Arch installer ~800M [2]

0: https://support.apple.com/en-gb/HT201372

1: https://www.microsoft.com/software-download/windows11

2: https://archlinux.org/download/