I agree, it can't rise forever. The rises will taper off and we'll reach some rough equilibrium of hashrate.

It doesn't have to rise forever at 15% though. Only for the next 12 months,
or less if there's a couple of bigger leaps early on, or if your miner arrives at the end of Sept. instead of the beginning.

This time last year the network hashrate was 150TH/s. Today it's >600x that.
You don't think we can see a 30x rise over this coming year with all the manufacturers now on the scene?