I've found that sometimes the opposite can be true (in a good way!). At one workplace, I introduced Fish to some fellow developers who until then mostly saw using the command line as a strange, difficult, and unpleasant part of their jobs.
Once I got them started with Fish, they were happy enough with default interactive behaviors, convenient documentation, and simple scripting syntax that it encouraged them to do a little more scripting, and eventually to customize some of the aesthetic stuff by writing custom prompts!
It was pretty cool to see.
I went through a "distro hopping" phase at some point with Linux and ended up settling on a system with very little custom config. It's close to the defaults so I can work very comfortably even in a random server.
Of course this is not ideal. If you have a tool or set of config that you like, then you should use it. I've just found that the human brain can overcome bad UX quite well with a little effort ;)
This is such an incredibly odd perspective to me. I use zsh and have not touched my shell config in years. Messing with configurations to get things working to your liking is a one time thing. I don't even use plugins.
On the other hand, if fish doesn't work to your liking out of the box, and for many people it does not, there's no "messing with it" that's possible. You are forced to give up and use something else. Your reason to choose fish is only a good reason if you already agree with every minute choice the developers made and refuse to let you adjust.
What do you want to do that isn't possible? I also haven't messed with it in months if not more (fish in my case, not zsh) but years ago I messed with the prompt a lot to get it to my liking. (From a previous zsh config.) It was perfectly possible.
Which part of fish makes this impossible? You can tweak the startup, the completions, the key bindings, the prompt, and so on.
For example, to me, it is _insane_ that in 2021 async prompts are not a completely solved problem. The shell should provide a mechanism to do so easily, rather than duct-taping thin veneers over syscalls via a scripting language.
As for a replacement for oh-my-zsh itself, I had good experiences with zgen[1] but the fastest I've found is zim-fw[2] which produces acceptable start times for me[3].
[0] https://github.com/romkatv/powerlevel10k/
[1] https://github.com/tarjoilija/zgen
I haven’t tweaked my shell config in 7 or 8 months now.
This is a different mindset from the giant zsh configs, “plugin managers” and other junk that is wholly irrelevant to using the shell. You’d think that fish incorporating a lot of functionality that zsh has would manifest as bloating fish, but, IMO the reality is that zsh’s “bloat” is pushed into user configuration and the user is tasked with making it work.