He will 100% receive more comments and upvotes the longer he is on Steem so reputation 70 and 21000 Steem ain't even realistic anymore. It will probably be 72 and 40000 Steem Power.

More upvotes may not mean more Steem. If the price of Steem rises, more users get on board, there will be the same amount of new Steem split among more people. It may be that the dollar amount will keep improving while the Steem denomination will not.

Steem is fundamentally scarce.