1. Probably someone will be mining.
2. $25,000 ASICs have about the same cost of MHash/s/$ as the cheaper ASICs.  See https://en.bitcoin.it/wiki/Mining_hardware_comparison.  So it's not true that you have to buy $25,000 of mining equipment just to get in.  $1,000 or even $250 will buy you a stake at the table with the same proportional ROI as the bigger miners.
3. Maybe a little.  ASICs are a challenge mostly to non-ASICs.  On the other hand, as specialized equipment they make Bitcoin mining more energy efficient, which is good in a way, even though it reduces the profit per MHash since the MHash of the network increases greatly with no corresponding increase in mining rewards.

Also, you can mine with your own GPU.  The pools just make payouts more steady, as I understand it.  Otherwise you might wait months between payouts.  If you want to mine GPU, you should probably be mining Litecoin or one of its derivatives, not Bitcoin.