PC gaming is almost always bigger than the best selling console taken singularly, although it's normally smaller than the whole console market, except when the slowest cyclic periods of the latter don't coincide with the slowest PC ones.
About price for a gaming PC, it constantly gets lower, the overprice to make a work one become a gaming one is getting lower too, avoiding highest end GPUs it's already cheaper than most consoles, and after the first purchase a PC can be periodically updated for a fraction of its initial price.
About expansion of PC and competition from tablets and phones: China, India and other rapidly developing countries could make PC market even huger than now, and Android could end up unifying PC market with the mobile one.