As statistically likely as it is there is intelligent life out there, it’s just as statistically unlikely we’d ever run into them. Turns out, the universe is big. Like REALLY big.
Grusch alleges that some are held under lock and key by private corporations that have reverse-engineering affiliations with the gov’t. Others also seem to be ferried about for study by cooperating governments, such as the “five eyes” group (including the US, Canada and Australia) recently pointed to by a Canadian MP. He further alleges that some American researchers have been injured through the work.
I have read that it is highly likely that the lifespan of intelligent civilizations is pretty short, cosmically speaking. Which certainly seems to be probable with ours—assuming we ever attain the status.
My Wikipedia says the original estimation was 1,000-100,000, but current parameters put it at 15,600,000. And this is for intelligent civilizations, not planets.