And even going by the "more parity" metric, MLS is not hyper-competitive. It only appears so when compared to the top European leagues, where parity is close to non-existent. And even those leagues would appear to have more parity on a more superficial basis if they employed a playoff system.
Compared to other US sports leagues, MLS is only so-so in terms of parity. Two teams (LAG and DCU) have won 9 of 19 championships. Another team, NER, has won the East 5 times but never won the championship.
Similar dominance in MLB leads to incessant whining.