I think talent outweighs coaching about 2 to 1 in HS basketball. Any coach with a host of talented basketball players can "build" a great program. Coaching becomes a bigger factor when the talent level on the floor is in the same ballpark as your opponents - state tourneys for example.
Just look at the East Valley BOYS this year. Coach Elder has been on board for quite a few years now and has a pretty good reputation. Championship game a few years ago. This year they are 0-XX. You gonna tell me he forgot how to coach? No.