At least from my experience, wholesalers are a mixed bag.
Most are in it for the immediate profit and don't care (or do not know any better) about their long term reputation with the "real" investors in their market. There are a ton of wanna-be investors that want to be "sold" a good deal. These poor folks are prey to the "wholesalers" and buy things based on the wholesaler's ARV and repair numbers. They will do one or two deals and then realize they are losing money. Seems to me most get burned out after losing their hard-earned money, but some actually learn from their mistakes and learn the real numbers themselves (I fall under this category).
Unfortunately this situation seems to be fairly prevalent because of the lack of real deals on the MLS. That being said, most licensed residential real estate agents that deal with lower-end "investment" properties also lack this knowledge as well. I offer on nearly every REO with some meat on the bone in my area of interest (two counties). 9 times out of 10 I am out-bid, and really don't see how these "investors" that are buying these properties are actually making money based on what they are paying (unless they are doing the work themselves and buying a "job"). In many cases, the starving realtors that need commissions sell crappy deals off the MLS to ignorant "investors" in a way that is almost as bad as the greedy wholesalers.
On the other hand, I have purchased three investment properties in the last couple months from wholesalers and only one from the MLS that were actual deals. The wholesalers were not super greedy and maybe even possibly took my lower offers because they knew I would close quick with no B.S. Don't get me wrong, during this time frame I've sifted through 100+ wholesaler "deals" and EVERYTHING on the MLS during this time frame which is a good bit of work.
It's of my opinion that there are too many toxic gurus pitching get-rich-quick real estate that takes advantage of sellers and buyers alike. The good news is that it's easy to spot the real investor/wholesalers from the fakers. The good ones only wholesale because their deal-flow exceeds their ability to buy/rehab at the time. The wholesalers that do not rehab themselves are usually the ones with little resources and knowledge, thus their numbers cannot be trusted.