Of course it can be tinkered with, but it wasn't really designed to be tinkered with in the same way that you can with a traditional Linux system. It's designed to keep users from messing with system files with its strict containerised workflow. It's certainly not targeted at users who'll want to hack systemd services, customise kernel modules, tweak system files under /etc and /usr, or even compile software from source.
I acknowledge that it's possible to create highly customised and reproducible systems with immutable distros, but it's a paradigm shift compared to a traditional *nix system.
I've spent 20+ years refining my knowledge of linux and BSD, I haven't got the patience to start over with these types of systems.
Please don't get me wrong, I'm not at all criticising these systems for being different. They serve a completely different purpose —one that's just not for me.