Possibly, but at some point they'll make themselves so painful to do business with that they will start to lose contributors. Especially if they can't keep sales up.
I think I said once before, the worse they treat us and the less we make, the easier it becomes to decide to leave (exclusivity or the site).
I don't think enough people would leave. We're talking about 90,000+ contributors. How many of them are actively aware of every change istock makes, every misstep and every underhanded trick they pull to take more from buyers and contributors? I think most contributors go on their merry way, ignoring the forums and blissfully unaware that some of these things take place, or at least not caring much and believing the pathetic explanations and excuses that HQ presents in their emails.
This is the thing that these companies have figured out over the years, that they can do whatever they want and the repercussions they face for their actions will be minimal. istock and fotolia cuts royalty rates and how many people quit? Maybe a couple hundred? Probably not even that many? Fotolia changes the rank levels. DT changes every fraudulent credit card sale back to contributors. istock keeps jacking up prices (anyone notice the increase in vector pricing a few weeks ago?). And what happens. No buyer exodus. No contributor strike. Barely a blip on the twitter feeds.
They can get away with murder and they all know it. It's why SS stopped giving regular pay increases. Why should they? Most people barely noticed that rates haven't risen as they did in the past.
And these companies are pulling it off brilliantly. They keep feeding us this B.S. about how it's because they need more money for marketing to sell our images and ultimately make us more money. Or that they need to do these things to ensure a profitable future for us and the company. Not everyone believes the lies, but enough people do and just hang in there and hope for the best.
And here's the really brilliant part of it. These companies have enough product to easily absorb any large loss of contributors, and they know it. If something major happened that inspired 10-20% of a company's contributors to leave, they still have more than enough product from the remaining 80-90% to carry on like nothing changed. Buyers would hardly notice a difference, they'd keep on buying and spending those credits, and in the meantime the company would go right on replacing those lost images with the latest batches of recent uploads from the folks who stayed on board.
That's microstock these days. These companies always had the upper hand. They always held the best cards in this game and we have always been at their mercy. The difference today is that everyone is significantly more aware of just how far they can push that advantage, and how much more they can take from us and keep for themselves.