I do agree, I wouldn't go that high, I think my dad justify's it based on his income but more importantly the gas and cost to drive a car + the health benefits, he also keeps everything he has in mint condition. You can usually get a pretty decent resale (not that he sells his, he always uses his 2nd oldest bike for a "rain/bad weather" bike) on these bikes.
and IMO.... once you get older and as long as your not a douche and just buy stuff to brag about it, you can damn well do what you want with your money.