In many cases the balls would likely not return.

Most houses have no shortage of balls left behind by league bowlers that would hook plenty.

 When you think about all the money it would take initially, then all the time you would spend on maintaining them, "performance" level house balls just wouldn't make practical sense.

  Not trying to hijack this thing, but this is one of the things about "modern" bowling.

 When I was learning to bowl, the house balls were just about the same thing that you could buy from the proshop. You could walk in off the street, rent some shoes, and get very close to experiencing what bowling was like at even a higher level.  All you could really do was practice and develop/hone your skill level. Not anymore.
 I honestly think this is part of what has lead to having two separate and distinct factions in bowling, the recreational "game, and the serious "sport".

If hp balls from the resin era are left on the racks for free (by bowlers and proshop dumps) and no maintenance of any kind is done to the ball it will still work perfectly for this intended purpose. 

The balls will out hook the urethane no core house balls by a lot.

They see that on TV with the promotion of BELMO.  I see it here every night I am bowling it is funny.  People need to learn the fundamentals of the game first. An it is not cost effective for centers to provide anything other than houseballs.