My wheelset cost me $100 including the shipping. R501 with R500 rims, R501 hubs, bladed spokes. I doubt I'll get good enough in 2014 where my wheels are holding me back. OP asking about $400 vs $2000? Yeah... I'm not even close to his cheapo wheels. When rims wear out, next wheelset probably Shimano RS31, which cost $200. Oh well.

I would imagine biking is no different than any hobby, diminishing return. Diminishes really fast after some price point. My guess $500... Since can get really great wheels for $500 from wheel warehouse and William's.