At the end of the day, frequent flier programs exist solely to incent loyalty as bhatnasx said above. If an airline decides that they can buy that loyalty cheaper, then they will go ahead with that plan. Personally, I think the point-to-point mileage thing wouldn't happen because you'd see a lot of fliers loyalty shift in a heartbeat to a competitor willing to status match. There is simply to much competition in the domestic market amongst carriers with incredibly similar products and programs. For the same reason, I don't see the 500 mile minimum on miles going by the wayside anytime soon.

Then again, 10 years ago we all would have said the same thing about an airline making you buy a meal if you wanted one.

If airlines don't like people taking advantage of this stuff, then they should simply not post cheap fares with absolutely ridiculous routing rules that allow it. Why allow four stopovers to anywhere domestically? It isn't the consumers' fault for taking up the airlines on their officially sanctioned idiocy.

peace,
~Ben~