Landing them didn't bring the sort of cache that landing a kid like AJ would bring to BYU. Those guys kind of came out of nowhere to become high level NBA players, but you better believe that Fresno State, Murray State, and Iowa State have used those names to leverage better recruiting classes and to increase donor contributions over the years.
There's no doubt that Arizona State has benefited tremendously from being affiliated with James Harden, and I think Kentucky has benefitted from association with a long line of heavily recruited prep players like Jamal Murray, too.
Schools definitely benefit from having high profile players go through their programs enroute to the NBA. Think of the effects that Kawhi Leonard has produced for San Diego State, or Michael Jordan for North Carolina, or the Fab 5 for Michigan.
BYU has proven to be very savvy when it comes to leveraging marketing and PR opportunities. You can't buy the kind of publicity that landing the #1 overall recruit in the land, and making a deep run in the tournament would bring to the program. Especially if AJ goes on to have a Kawhi Leonard, James Harden, Hall of Fame type career.