Sales drop for sites after Amazon implements Affiliate API throttling

Isn't it bad practice to make an API call for every page view? It would be better to make one API call and cache the results locally for a set interval (e.g. 5 minutes). The pricing data is not likely to change very much in 5 minutes or even an hour, and for a busy site (apparently his site occasionally makes 2000+ requests to Amazon per hour) it would reduce the number of API calls dramatically. For example, if users do 10,000 searches in an hour for 100 distinct products, instead of doing 10,000 API calls, he could just do 1200 (12 calls x 100 searches).