From a pure health perspective, keeping schools locked down indefinitely probably is the right call. But health isn’t the only factor at play here. We also have to factor in society, economics, learning, etc.
If we keep schools closed into the fall, we’re looking at basically throwing away a year of learning for today’s schoolchildren. That’s a pretty extreme thing to do and we better have a really good rationale behind it if that indeed what is decided on.
Regarding opening up in general, doctors have a huge role to play, but there are lots of factors at play. We have to account for the full spectrum (accounting for economics, psychology, etc.). Locking down until/if a vaccine is almost assuredly the best move from a pure public health perspective, but that doesn’t mean it’s the right move for society at large.