As soon as it's not profitable to mine, the rigs go off. Without miners, bitcoin grinds to a halt, so why would I want to buy in at that point?

As has been pointed out repeatedly, if you are in this for speculation you should not be mining, since the speculation return is better .... as long as the market is performing.

As a miner I make a different bet, that the pool of miners will stabilize at a point where I can make decent money mining, if I can't do that, then I shut down all but one core and leave it for up to a month, if the market does not recover in 30 days, that goes off too, and bye bye bitcoin.

What kind of silly logic is this?
A product value is not defined by its cost to make it.

Bitcoin is very much supply:demand.

this is why there is difficulty

It's called emotional attachment, nobody said it is logical in any way. You spend X resources to obtain Y goods. Would you protect your involvement with Y goods by capturing any X resources with a lower value than that of Y goods?

Or better put: you are surclassed by cheap chinese workers that make your product cheaper. Do you continue to make your product in an expensive way, or do you start trading the cheaper version in your business process, assuming both products have the same quality, which for bitcoin is true.