I would simply have to disagree, I can't think of any aspect of climbing that has benefited from crowds and a large population of less skilled and self-responsible climbers. What I have seen is an endless requirement for the continous "development" of bolted routes to sustain the [commercial] output of gyms. This is a dollar and entertainment driven machine the net effect of which has steadily corrupted what climbing was all about. Sure the folks that rise to the top are capable of great things and do come around to looking for more "adventurous" endeavors because they get bored senseless. But the achievements of the top few of a very large pyramid isn't the issue, it's the ongoing impact of the very large base of [gym-supported] novice and intermediate climbers. Bolted on holds, route directions scratched and painted on the rock, inappropriate bolting. Now, you can paint all such incidents as abberations, but I call them unavoidable and direct affects of a larger population - more people, cluelessness, vandalism, and bad choices. It's more a matter of statistics than judgment.
From a statistics perspective, the population base of climbers required to advance climbing from 5.10 to 5.12 was relatively small with a large percentage of that population able to climb at a high level with a relatively low toll on rock. The population base behind the push from 5.13 to 5.15 grew enormously with a very small percentage of that base able to climb at a high level. Again, it isn't about the impact of the small percentage of folks that climb at a high level today, it about the impact of the vast majority who need gyms and bolted routes to sustain their identities as climbers and toll it continues to take on rock.
To lump together all beginners and novices, and say they have no respect for the rock they climb on (or aspire to climb), is absurd. You were a beginner once, right?