It's much more complicated than that.

>> If an undergraduate program's graduates don't earn more than workers who never went to college,

Lots of things affect earnings. Obviously education is one of them, but it's not the only one.

Location, economic environment, social status, personal network - all are factors. In other words comparing unequal things leads to unequal results.

For example, a first-generation college attendee gets a solid job working at a non-profit helping others. Someone else in the same town goes straight into Dad's profitable factory as a manager.

Of course those might be outliers. We can use statistics to smooth things. But equally we can use statistics to show anything we want.

Yes, there are lots of really crap colleges. There are colleges that specialize in nonsense degrees in useless subjects. (English Poetry you say? Hah. Poets never made any money...)

But equally there are lots of community colleges, taking in marginal students, giving them opportunities where others won't. Some, maybe most, of those students won't make it. But some will.

The effect of a rule like this is that colleges are forced to game the system. To exclude those who might fail. To reduce social mobility.

A cynic might even suggest this is the real goal of the rule to begin with.