Re: "as it is unlikely that there are more than about 16 such objects across the entire sky"
Yeah just like the GoldiLocks planets.
You used to get told there would be hardly any but when there are more stars than there are grains of sand on all the beaches on Earth. There might be more GoldiLocks scenarios that people realise.
Dr. Jason Marshall, aka, the Math Dude. According to Jason, there about 700 trillion cubic meters of beach of Earth, and that works out to around 5 sextillion grains of sand.
I don't want to sound like I am knocking the research but I am sure its quite a big place out there.