I don't know what you do but I maintain 3 projects based on create-react-app and have done for 18 months. Together with a couple of senior guys and some younger devs (both guys and gals) I keep them updated, build new features, rewrite stuff to tsx (we got the projects handed down) and with one single exception I never even thought about the build system.
I don't think they were saying create-react-app is bad or unusually fragile. It's that there are problems in building increasingly complex 'quick start' setups with the goal of making them accessible to people with less experience.
The less you know about how the internals work, the less you'll be able to intuit about what you can and can't change. For many people who just want to make "an app" this doesn't matter, but it also means that a lot of quick start setups optimize for particular approaches that are built on top of particular sub-sets of how apps are built. So people leave the experience knowing more about how a particular component library than they do about the language or the requirements of mobile, or whatever.
Or, to put it another way: increased complexity also increases the difficulty of investigation and modification. Making it easier to get an app 'somewhere' can make it harder for someone to understand what the app does to get where it's going.
