Like Vampyre mentioned, most centers don't care about the league bowlers. They can make more off of open play, that is if they get enough people coming in and bowling. There are even some centers that have opened in recent years that don't allow any leagues and charge per an hour for one lane. They also expect to make more money off the the bar and snack bar from open play bowlers.
All too true. The center in which my Sunday-night league bowls is much like this. I was trying to track down some information recently on PBA Hall of Famer Mike McGrath. In the process, I found that for several years he used to manage the only bowling center remaining in San Francisco. It doesn't have any leagues and doesn't want them.
There are some centers out there that go against the norm though and treat league bowlers very well and the center managers try to help the leagues grow and will try to even recruit leagues from other centers.
Fortunately, the center at which I bowl my Wednesday-night league and the vast majority of my practice sessions is like this. It's known around here as a bowlers' bowling center as opposed to having the more general entertainment base. Hell, the center where I bowl Sunday nights doesn't have a Pro Shop
. They have a White Dot, a Maxim and a T-Zone on the wall behind the cash register w/price tags on them.