We buy the new stuff because we want the new stuff, not because we need it Certainly there are advances in the technology but with the exception of Wilbur Allen's invention of the compound itself all of the inovation since then has been incremental. You have to look at at least 5 to 10 year periods to see appreciable improvement. Manufactures would like you to think you need to buy every new model when often times the changes by year are nothing more than cosmentic.

Here's another thing to keep in mind. The rate of improvement at least with regard to the speed a bow will throw an arrow has to be slowing down. Early on 200 ft/sec was pretty unusual, now 300 ft/sec is pretty common. Regardless of technology the maximum speed a 70 pound peak weight, 7" brace and 30" drawlength bow will EVER shoot a 350 grain arrow is less then 400 ft/sec. That's with a perfectly square power stroke (not possible) and 100% efficient (also not possible). As the technology approaches the limit (I'd say 370 ft/sec is more realistic) what improvements are made will be even less noticeable.