Many package managers require sudo, sure, but there is no good reason for them to in a modern linux system, and not all require this.
Even with systemd, you can use systemd --user.
Issue is that it increases friction and you need sudo anyways to set the capabilities.
Most web servers would happy to run unprivileged with only CAP_NET_BIND_SERVICE
setcap 'cap_net_bind_service=+ep' /usr/sbin/sshd
Could even run it as a daemon unprivileged from a home directory with "systemd --user"
That said if you have multiple users and want every user to have their own sshd reachable on port 22 on the same machine you probably want to listen on vhost namespaced unix sockets and have something like haproxy listen on port 22 instead. Haproxy could of course also run unprivileged provided it has read access to all the sockets.
That stuff needs to change very seldom, so when you do need to change it you just generate a new tiny rootfs image in a few seconds and reboot to pivot to it or maybe have a kexec trigger if you are feeling fancy.
For my primary workstation the entire disk is my home partition and I boot my latest rootfs from a flash drive. In other cases network boot.
The bigger issue is that if you want to install or update system-wide packages, many of those will be used by privileged processes. Suppose you want to update /bin/sh. Even if the only permission you had is to write binaries, that'll get you root.