I understand that you personally are fine with it, but this is apparently a trigger for me, so please accept my apology in advance for offering commentary.

• if you don't like it, you can use something else:

This is only really true for desktop PC hobbyists. SteamOS is responsible for a huge spike of Linux usage recently and that is Systemd-only. it's true that you can install something else but it'll be a significantly worse user experience. This is the case for basically any handheld Linux device, and all corporate investment is going to systemd based distros.

• if systemd starts to get bad, less people will use it:

The alternatives are less polished and switching distros is a relatively costly proposition if you are not a hobbyist (in terms of opportunity cost and time spent without a functional computer). Handheld devices such as the steam deck are much less flexible as well.