The income from the masses was probably quite marginal, the income from the Nobility in tithes, dispensations (funny how you could divorce if you had the gold) and bequests was substantial. Once you had that income, and you factor in that their own commercial holdings were tax free in many countries, and you had a real wealth machine, but that is the key that BM doesn't have, The Catholic Church had the ability to develop income streams and hold real profitable land, religions in BM cannot.
You shouldn't discredit the taxes of the masses, imo. After all, how did the nobles become rich? By taxing these very same masses. Per head, they contribute a lot less... but since they are so many more than the nobles, it kinda balances.
