This would also give those mining altcoins a nice market to convert their coins to btc and subsequently cash out.
I guess the question is, if bitcoin drops, will everything drop? Or will spreading your stake around the altcoin minefiled be enough to protect against huge losses?
Miners and mining hardware makers don’t actually care for bitcoin from a philosophical point of view, so they have no incentive to use it as a currency. It’s literally just a means to an end for creating value to them. If they were growing tulips instead, you’d see them investing in farming techniques just as happily.
There were some rather unamused comments at the time from miners who got their first experience of Bitcoin Cash by having to use it to buy from Bitmain, questioning whether it was always this terrible given that all its very vocal boosters had been claiming it was the fast option compared to Bitcoin. (The usual response was to argue that the block speed varied between a minute per block and the hour+ one and they were just unlucky - which technically it did, it's just most of the time it was in slow mode and the brief fast intervals were days apart.)
Commodity futures only work when you produce a consistent amount.
I haven't looked too closely at how difficulty adjusted after previous order of magnitude efficiency gains, but the risk is certainly there.