I'm not hating on Rockford's amps, I'm hating on the way they go about disspelling myths ...
Comparing by MSRP from 1990 to MSRP from 2005 is retarded ... If you compared the anything from 1990 to something for the same price today, just about anything is going to use better technology and be more capable. Amplifiers, cars, computers, speakers, sewing machines, TVs, microwaves, etc.; it doesn't matter.
However, comparing EQUIVALENT models is relevant (i.e. Punch 45HD to Punch 45 25-to-life). Comparing your current product to similar products currently made by other companies is relevant. Doing demonstrations to prove the advantages of your product is relevant.