Where it becomes a problem is when the airline decides they don't want to pay "too much" and start bumping people involuntarily. That should be illegal. If a flight is oversold and nobody will accept being bumped for less than $10,000, then the airline should have to pay $10,000 to resolve the situation.
As it stands right now, the whole thing is skewed in the airlines' favor because they have a nice, low cap on payouts.