No... I assumed the blocks wouldn't be full, so there would be plenty of room for no-fee (or minimum fee) transactions. Translated: Room for spam. Usually one will not pay more when they can pay less. I assumed (perhaps wrongly) that you were the one suggesting blocks would always be full since you said, "In both scenarios we would be paying fees to the miner."
Yes, but it grows faster with bigger blocks, and much faster with much bigger blocks.
Maybe that's because there isn't enough of a market for big players to get involved yet?
I'd argue that they have very little power compared the economic majority. One wrong step and they can be obsoleted completely.
A block chain based business that builds it's business model on an assumption that it's transaction will be included in the next block every time should probably rethink it's business model.