Trouble is, there are already too many people who use the word 'socialism' wrongly, because they have no clue what socialism really is.
Amazon's *excuse* is that if all members subscribe everyone will get a better deal (still not socialism, and definitely not a co-operative because it's not co-owned and no customers get a share in the profits), but their theory is the same as every gym on the planet: the more members who subscribe who don't use the service, the more money we make. People who get more than £80 worth of value out of Prime are going to be few and far between, and fewer and farther between the more services are bundled into it.
So, in shore, still not socialism, not even in the laziest formulation of the word.