And I think it's fine to be frustrated with stupid VC spending, but to the extent it is actually a problem, it shouldn't be sustainable (it would be replaced by less stupid spending if it were truly enjoining advancement).
The VC stuff... I'm not sure that it's not sustainable. The way VCs are selected is not totally efficient (I would say, not even very efficient). More than that, successful exits for VCs don't always mean that a product or service provided value to the world at large (or was a good use for limited engineering talent), there are lots of ways for a VC to get a successful exit without that happening (including a follow on investing giving them liquidity, before there is even a product on the market for example, or the company being acquired without having developed anything useful).
If they are wasting tons of money then they probably aren't the thing limiting advancement.
There's the problem of what "better" should mean, but private investors aren't going to fund government for fun (or similar), so many of the alternative meanings of better can't really be expected to inform a discussion about private investment. Like maybe stupid VC spending is evidence that tech companies aren't getting taxed enough, but that is solved by raising taxes, not by hand-wringing over questionable products.