> It seems equally likely to me that conditions in the Universe just weren't amenable to life until relatively recently.

It's at least 4b years old on earth, that's not "relatively recently"

We've been technologically capable for less than 200 years, that's nothing in the grand scheme of things.

We could have just missed them by a few millions years and we would have no ideas at all. There might be 10 ancient Egypt tier civilisations out there right now that might develop radio tech by the time we're extinct or back to low tech.