VCs have no idea what to do with their money, on the other hand potential founders gravitate towards dev tools because it's a space they know well. It's not necessarily that they're seeing value (not saying that there isn't value there either).

Think of it as

[startups skewing towards dev tools] >> [clueless VC] >> [many dev tools startups get funded]

This actually works even if they aren't clueless - they can only respond to the opportunities presented to them and that input sample will be biased.