A large part of it is that big companies have given up on trying to innovate (they just buy innovations, at a panic price) and the people from whom innovation typically came are now a pariah caste of almost-unemployable miserable geniuses. Even worse, those people can't raise funding anymore because they've been outcompeted (for attention, press, and funding) by people with superior social polish but shittier ideas.
VCs are private equity guys. For deciding whether two $300-million biotech companies should merge, they're probably the best people out there. It's not that they're "good" at making those calls, but that the companies are so complex and unusual that almost no one is, and they're the most adept at figuring out what's going on amid the chaos. They might be able to tease out a +0.02 correlation in decision-making while the rest of us would get zero. For figuring out who has the competence to start a tech company? They're in the dark. Not a clue among them. It's not what they learned in business school or McKinsey. They'd do 100 times better to have a person like me do the talent scouting/vetting, but for a variety of reasons that will never happen.
The real evil isn't VCs so much as it's the replacement of R&D by M&A, representing a wide-scale trend of engineer disempowerment. Being a software engineer used to be an R&D job because non-engineers understood that they didn't know how to do that job, so it got a lot of autonomy and trust. Now, it's being treated as commodity work, and the result is a catastrophic dilution of the industry. VCs aren't singularly to blame for this, but they certainly didn't stop it.
It was actually a lot better, for engineers, to be in R&D labs of large companies than it is to be an engineer at a VC-istan startup. You had more career growth and more opportunities to learn stuff. Don't be fooled by the bullshit equity handed out now. Sure, these R&D engineers didn't get rich at 27-- they had to strike out on their own to do that, and many were happy being upper-middle-class technology researchers as a lifelong career, so most never did-- but most VC-istanis don't either.
We need to bring back the R&D flavor of the software industry, or we'll have lost the industry for good.