Why can't we all have the same test?

So my son had to fly to Japan. I found out he had to take a Covid test before he flew. The results of the test are done in 10 minutes. So why isn’t this available to everyone taking a test? Apparently, it’s only used on our Military. I am grateful for that but is there some reason this can’t be produced on a mass scale? Or at least for every passenger flying on commercial flights?