I’m sorry to have to say this, but the presence of netboot.tar.gz as well as netboot/ubuntu-installer/${arch}/{linux,initrd.gz} was one of the best things Ubuntu inherited from Debian, and one of the reasons why I encouraged the use and deployed Ubuntu on servers, workstations and VMs all over the globe.
It used to be super simple to bootstrap Ubuntu install, whether it was just a local PXE, workstation brought up from nothingness by simply loading linux & initrd.gz from EFI shell, or automating some very specific cloud image generation.
Good old times; one would simply need to load ~60 megs of stuff over the network or USB drive, perhaps choose an option or two in a super simple text menu that would actually get displayed on any device out there, from simplest serial-over LAN console to the most expensive display on most expensive GPU money can buy, or perhaps leave everything to options pre-configured in a simple text file, and voilà, there is your machine up and running, happily installing stuff while you do spend your time doing something non-trivial and slightly more important then clicking buttons on some GUI, rinse and repeat for each and every machine you may have to set up… And it worked in a same reliable and predictable way for what seems to be decade and a half?
It did not cost Canonical anything to keep this Debian feature. Actually, it seems to me that it must cost quite substantially more, in terms of network bandwidth wasted, to download all these ~900MB-ish bloated ISOs where it could have been just ~60 megs each time there is a new release of Ubuntu, multiplied by all install “locations”.
Oh, yeah, and it will also cost Canonical yet another loyal and influential customer lost, unless this is fixed by 21.10.