Keep in mind, ASICs only showed up AFTER the first reward split, so half of all bitcoins ever went to CPU, GPU, and FPGA miners.
Well even after all the coins are distributed the miners will still continue to maintain the supply because of transaction fees.
I see ASICs as a natural result of the Bitcoin protocol. It's a free market. As long as the networks hashing power is distributed amongst different competitors, this will keep the network healthy. Let's say ASICs didn't become popular, the network difficulty would be lower and it would make it easier for a rich/resourceful entity to attack the network. We need our miners doing everything they can to make the most efficient, powerful, and distributed network as possible.
I don't think there is anything natural about the bitcoin protocol, and it is not perfect and is not future proof. Its designed by a large group of people.
Also as an ecologist I can tell you for certain natural systems don't have a default equilibrium, they just have buffers to prevent too much change at once.