So we only have one data point of a planet producing what will quite possibly be a spacefaring civilization or, in the very least, one able to comprehend as such.

But if you accept that the Dyson Swarms are a likely outcome then we have a while bunch of negative data points in systems within even thousands of light years of us.

That then brings into focus the hypothesis about Dyson Swarm. Such a thing can be built incrementally, requires no material stronger than stainless steel and requires no energy tech beyond solar power. It is a massive engineering challenge to be sure but not requiring new physics is significant.