They can't lower the match times because it would screw with the economy.
In theory they could reduce match times and rewards, but then it would feel like nobody was getting rewards from short matches and more people would complain.
Yup, that would be a issue. Although one could argue that the economy is pretty messed up right now. Just think how many times you have to play those few strikes or multiplayer maps over and over and over just to get enough reputation and currency to buy a set of armor from the merchants.