Unity somehow manages to break the API of their own features so bad every year or so that their own tutorials don't work. You have a solid baseline API that has existed since forever (with known limitations), with stuff like the legacy render pipeline. Every attempt to reform it has only introduced confusion, complexity, and is at some point between experimental and no longer supported.

I don't agree with you on the Asset Store, for the same reasons - the rate of breakage means that things that are not constantly updated no longer work - and multple versions need to be maintained for parallel engine versions. That combined with the dubious economics of Asset Store (I don't think it makes financial sense to even make these things, let alone maintain them), they mostly end up as abandonware.

And on the Asset Store if you make something indispensable (which is more often than not something the engine should'have OOTB, like competent text rendering), one of the following things will happen:

- Unity will buy you out, and plop your asset in the engine, without doing any integration work, and will stick out like a sore thumb (TextMeshPro). Good for you, bad for consumers, and sucks if you were making a competitor

- They build an in-house solution, that you obviously can't compete with, and will have a huge leg up on you because they have engine access (sucks to be you)

- The engine will never have that feature, because 'you can just buy it', meaning you have to either spends hundreds of dollars/euros on dubious quality assets or hunt for open-source versions with generally even more varying usability. UE4/5 has a lot of these built in, and AAA quality.