Yesterday there was a car with a semi-nekkid lady on the front, with higher res skins I would have seen twice the detail! Brill. Reason enough to pay extra
Seriously though, looking at the cost - it is very high if you just take into consideration the amount of bandwidth used. ie 2000 skins at 100k average each lets say (have no skins to sample average size), would be approx 195mb. Equivalent £5ish per GB. Buying bandwidth in large amounts you can get it for a lot, lot less.
However if the profit helps elsewhere such as hardware improvements (goddamn slow online server listing) I would have no problem paying, the few helping the many etc.