Was it ever actually fit for that? The VC economy basically always served one type of company, consumer-focused "lifestyle" or service 'technologies', and nowadays a lot of the institutions like a16z just appear to turn into straight up media outlets.
VC success in the industrial sector, biotech, military or scientific applications has always been muted compared to the kind of money that flows into the leisure/consumer/entertainment economy.
If you want to solve complex problems bet on Darpa or academia or bring back the corporate research lab whose demise is one of the real big problems today.