I've heard the ratings on Amazon can make or break you, so I think most people are at least trying to get quality by taking the ratings into account.

The ratings are hilariously gamed. Vendors will use coupons and discounts to get you to leave a positive review, while negative reviews are often reported off the site or the submitter is hounded by the vendor.

I do know that people use these ratings when making decisions, but the correlation to quality is fuzzy, at best. I can't imagine people will continue trusting these ratings forever.