Re: Thinning the herd
It might help to take a look at basic economics. Mature markets will naturally have a revenue/customer threshold beyond which the market as a whole will not support without external forces at play (e.g. regulation, technological advances, etc). The market can become monopolized by one competitor, but most governments don't permit true monopolies and haven't for many decades. Instead, the best competitors either force the lesser competition out of business or buy them out (i.e. consolidation).
Apple is not and never will become a monopoly. Their business model will have to change significantly for this to happen and I suggest that it would countermand the relationship with their current target customer base (i.e. fanbois and the like).
If I were Sony and HTC, I would look for someone to buy that part of the business first, so you can get some value back from the investments already made. Simply exiting the market by way of layoffs and production stoppage is too painful from a financial point of view.