The companies that make them are not terribly concerned about that. The only thing that matters is whether people are still buying them or not. So they will continue to be sold until nobody is willing to buy them. Thier business model (in most cases) does not depend on the profitability of the device.
or even the bitcoins they produce, which is the disturbing part of the equation. It would be interesting to know how many suppliers in the whole development and production chain required payment in filthy fiat as opposed to btc.
The problem with mining for profit is that it's rapidly becoming a race into a brick wall in terms of investment return, I'm sure there's a slew of other not entirely accurate analogies too.
The truth is though that bitcoin may be incorruptible and be around forever but the only way bitcoin mining is ever going to return any sort of profit
from mining at this stage of the privileged, electronic obsolescence arms race is if it becomes a mainstream currency exchanged in large volume for goods and services worldwide, I know that is happening to some extent but as has been said, that is currently just a drop in the Olympic sized swimming pool and its true value is largely untested. I mean ultimately who cares about increasingly worthless fiat or how many "fiats" it might be worth. What really matters long term is what you can actually buy with it and what work you can do that pays btc.
At this stage in it's life it's really just a concept that's feeding itself in an almost closed loop and the challenge and big test for bitcoin as a crypto-currency and the network security it needs to survive the inevitable attacks on its incorruptibility in future will be when there is nearly nothing left to mine and the economics no longer justify the expense of doing so for the many small scale players.
Interesting times, my only hope is that it breaks the backs of the usury crooks, living high on the loot from their government backed money cartel and debt slavery system.
