Mmm, is this really the case? It could also be that if mining value becomes lower than BTC value, then some miners will stop mining. Miners stopping mining will reduce the protocol's difficulty, which will make mining value easier to meet.
there are many layers involved.
but there gets to a point where those remaining miners have a bigger slice and decide they want to keep that bigger slice by expanding hashrate because they can afford to upgrade to keep the bigger slice. which then plateu's/levels out a dip to a new bottom that is non zero
in both the market and mining. there is a limbo area where seller become buyers. and lack of hash competition becomes upgrading hash