>Is anyone else

Yes. Minor thing but I find this sort of passive aggressive framing more irritating as I've gotten older and crustier. You're on a global network of billions. No matter what it is about something with as much uptake and variation as shells or millions of other things, of course there are definitely other people doing the same as you. Rather than a kind of silly/weird seeking of validation just assert what you do and why. It's particularly galling when yes you're probably in the flat out majority overall, defaults are powerful and there are almost certainly a lot more people who just dip into shells once in a long while and never customize a single thing than who go even as far as you do.

>mostly rolling with the zsh (not oh-my-zsh) defaults?

You could ask the same thing about all sorts of powerful tools and environments, from powerful CLI tools (not just shell but Vim or Emacs) to CAD and graphics programs which are famously adaptable, and the answer is always that it's a matter of an individual finding their comfort place on a spectrum of tradeoffs between ease of moving between environments and meta-work cost vs future efficiency/comfort benefits. The more one customizes to their exact needs, the more fragile the environment in moving across systems (efforts in portable environments can help on the technical side though they're not a panacea, but even that won't help with just plain not being allowed to customize a remote work area). It also means when outside of the heavily customized environment productivity may drop quite a bit, a lot of muscle memory goes to things which aren't there. It also takes meta-effort, time and resources spent on improving tools themselves rather then using the tools to do the desired tasks one reaches for the tools in the first place. Of course, some level of effort is required by any specialist to learn at least standard tooling and knowledge, but rarely is mastery of a tool an end in and of itself vs a means to do something else with said tool. Ideally there should be a positive ROI on time invested vs making that back later, but that won't necessarily be the case with something rarely used or where needs are basic.

Conversely though customization, getting really comfortable with the full power of automation computers offer and knowing how to rapidly match that to any new work can have major productivity boosts down the road. And sometimes give new perspectives on the edge cases and other tooling that is useful anyway, as well as just plain make things better fit individual needs and senses. And some people just don't move beyond their own environments much, or are valued specialists who would be allowed to bring their own environments and tool chains with them at any new job (encouraged/expected to even, that's part of the productivity they're being hired for).

No right answer to that now anymore than there was 10, 20 or 30 years ago. Personally I'm more towards the customization end of the spectrum when it comes to shell and general CLI environment, I'm not doing a lot on machines I don't at least have user environmental control over vs my own systems, and I've been happy to sink the time into really shaping zsh and other utilities to what I want. But I'm not nearly as far along as a range of other people either and I can certainly see the attraction of just using the standard stuff (and I do do that more in other areas than when I was younger too). Deviation has a cost and it's worth giving a bit of thought as to whether the cost is worth it. So nothing wrong at all with using something pure vanilla or close to it. But on HN in particular shouldn't be surprising if a lot of us do a fair amount of tweaking. And then search for a way to make that reproducible, sharable and clean to work with same as any other "software project", which leads in turn to various frameworks and such to help with that.