Or maybe the value of colonising a planet relative to the cost just does't make it worth it by the time you have the technology to try.

Maybe every advanced civilisation ends up turning inwards to simulations rather than outwards. Maybe there are aliens all around us, but we can't notice them, because we're living in someones phone, in the latest top-hit: SimHumans5000.

There's quite literally an infinite number of possibilities where we're not alone after all, and part of the problem is that we don't just not know the values to plug into the relevant probability calculations, but we don't even know all the variables.

An inwards turning civilization would be much more incentivised to collect all the matter they can since E=mc^2, and for them E is their lifespan.

For a civilization living for trillions upon trilions of years inside a simulation, intergalactic latancy is just a blink of an eye -- they have no reason not to distribute their simulation across the galaxy.

All of the burning stars would be just lost time for such a civilization

> I think the point is that they would have colonised Earth already.

Not saying I believe this, but are we sure they haven’t? There’s a bunch of fringe people who believe it did happen.

What would be the point of an alien ship travelling across the galaxy contacting just a select group of loonies?

Sorry, guess I wasn’t clear. There’s folks who think intelligent life on earth could’ve been caused by alien life splicing genes with pre-existing species on the planet. Still rather loony, just in a different way than the abducted folks.

We can see our commen ancestry with all life on earth. So not unless their idea of colonization was dropping some primitive microbial life from space.