Google's dislike of the affiliate model of marketing is well known. It has been the subject of online dialogue from as far back as at least 2011, if not earlier. I think it was Tedster who commented in here at one time that Google take the approach that they want to index and rank the merchant's own site and any further exposure of the products(s) is just so much duplication. The logic also says that if the merchant needs exposure, then they can buy Adwords.
In my niche the Penguin update was a massive clean-out of smaller, independent affiliate sites who have never resurfaced, and I suspect they never will. We are now seeing more reports of likely action against affiliates for "thin and/or scraped" content. OK… Google can run their business however they want.
BUT….
So can the merchants and in many cases, the merchant has made a conscious decision to use the services of a third party (ie.. affiliate) to expose their products to a wider audience. They could have used a marketing company, placed newspaper adverts, paid for a Yellow Pages entry, taken a page in a trade magazine, employed an Adwords specialist etc etc….. but they opted to use space on an affiliate website. That is their decision to make based purely on their assessment of ROI.
In the accommodation sector, it is commonplace for mom & pop to use their inheritance, savings or superannuation to buy the management rights to a resort. They usually come from another background and have no previous experience, especially with the marketing. It is a very common scenario to find those newbie operators deliberately seeking an affiliate partnership to shore up the skills in areas where they are lacking. It is a conscious decision, based on logic, and is an integral part of their operational plan. In a competitive niche the costs of Adwords is way beyond their budget so other options have to be considered.
But Google seems to be seeing the affiliate as having no value whatsoever, as being a pariah and to be driven from the SERP's. From where I sit, that approach is damaging the merchants as well and effectively removing one of the options available to them for exposing their products to the intended audience.
Is that a restraint of trade?