That isn't needed anymore. One person can maintain an entirely in-house solution and easily make changes and adaptations.
Drupal is used at large organizations with hundreds of sites, thousands of users, and multiple more-or-less coordinated development teams. It's actually a great target for agentic coding, because it has such a well-established internal API. It can definitely feel like an anachronism, but I think there are few projects that could replace some of it's use cases. It's the B-52 of CMSs.
I reckon AI must be much better now at this since it's doing all sorts of things, but I wonder if you still would need to have the repo cloned so that it can crosscheck with the source code. Since the knowledge cutoff should be around 2025, most of the stuff it knows should be plenty
If I'm thinking of building a single one off site, then yeah I'd probably opt to just let CC handle it without worrying about a framework which is overengineered for my current need. That's what I do with most of the personal projects I work on these days. But I do have a skill to build consistency around the parts that should be consistent for everything I host. Like package shape and types of hooks available for deployment. How sites are publicly exposed and DNS management.
Sadly none of this applies to me, so I wonder whether it makes a good argument when my question is "should I use Drupal for my personal hobby website".
Once you find you do have a need for something more complex (i.e. you have a team, want to give agents governed access etc), then it's pretty easy to go from a flat file to something more complex.
PHP is, in fact, exceptionally good as a language for creating websites.
But that rewriting the base system, every couple of years, was why I dropped it.
Nowadays, with LLMs, it may be time to look at it again...
To be fair, they did it once, from v7 to v8. But yeah, a major release does break APIs. I'm concerned with how Drupal Canvas is bolted on, but it looks like it's basically a content editor UI that is separate from the site admin UI, which is a good idea.
Also, there were a whole plethora of extensions (not just "plugins"). Some of those broke, while others, did not.
Can't answer the specifically "Drupal" part (as for me I once had a certain pressure behind me to use it, found it atrocious at the time and won't look to repeat that; if their software is much better / much more to my taste now, good on them). But in principle, at least from a certain app size upwards, I'd rather start with something working in principle, then improve on it.
That said, it might still be more difficult to get things right with Drupal than with some other softwares where you have better continuity between versions. At least traditional search engine results tend to handle version changes rather poorly meaning you'll get tons of advice that don't really apply anymore because they're years old. That happened a lot to me when trying to help out a friend with a WordPress installation.