Generations Full Art PSA 10 = $400?!

Hi All, I was curious to see how much PSA graded Generations holos/full arts were going for, I saw that in the last few months: Mew PSA 10: $199 and $299 Zapdos PSA 10: $350 Articuno PSA: $400

This led me to the following questions:

1. Why would someone pay this much for these cards when Mew isn't that rare?
2. How hard is it to get the generations full arts PSA graded 10?
3. Given PSA turn around time can be up to a few months will more people jump on the PSA bandwagon of grading generations full arts in the coming months?

If you have any other insights it would be great to hear, thanks!

Edit: These cards are being sold for the above value not just listed, although it says "best offer accepted" so i'm not entirely sure the exact price the cards sold at.

Link: (thanks to ReverESP) http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=pokemon%20Generations%20psa%2010&LH_Complete=1&LH_Sold=1&rt=nc&_trksid=p2045573.m1684