If you are talking about rotation on the landing page, sure, that would be great BUT it is not the priority this minute with the owner. Getting new products online is. Could FAA hire someone full time to do that and nothing else? Sure, but I doubt it would increase sales enough, (if any at all) to pay for that full time salary.
Now, if you are talking about rotating the search results in general then you can actually cost the site sales. From a customer and business perspective you want a degree of consistency in the search. If a potential customer searches for what they want, finds several choices and decides they will look again later before buying then they come back later and try and replicate that search and find completely different items then sales will be lost. The search does rotate based on the algorithm used but it can be a slow rotation depending on when new items are uploaded or items sell etc etc. That is not likely to change.