Right, that's what I'm saying: As more people join the network it becomes uneconomic to mine bitcoins, because since it's harder now, it costs too much electricity. So those with the least efficient setups stop mining.
So the price settles at the cost of electricity.
Then they reduce the number of coins per block. So suddenly it comes even less worth it to mine. Until the value of each bitcoin rises to match, causing people to want to mine again.
If the value of each bitcoin did not rise, no one at all would mine and the network would grind to a halt (no confirmed transactions).
Unless they have a mechanism to reduce the difficulty factor at that point. I'm not sure on that point.