Given that the estimated cost of building and launching the satellites is estimated at only 600 million dollars [1], it is estimated to take something around two or three years until it's been paid off, followed by two years of generating profit and the next five-year cycle starts (assuming that their estimate of five years life time per satellite holds [2]).

Personally, I think Starlink was the best bet SpaceX ever made. That thing will be a permanent cash cow.

[1] https://www.forbes.com/sites/johnkoetsier/2022/02/14/starlin...

[2] https://subspace.com/resources/spacex-is-giving-the-internet...