I think it's worse than that: DRM is serving a market of users ASKING to pay a lower price for renting movies instead of buying them. Many users are very happy to trade freedom of sharing with cost, and I personally don't think you can expect a business model based on an agreement of sharing restrictions to work without any layer of technical enforcement.

Even outside of movies, there are surprisingly few examples of successful artificial restriction policies without any kind of enforcement. Socially, people assume that they will be physically restricted from doing things that they are not supposed to be doing (from key locks to bank safes to packaging boxes with safety labels to bodyguards to keep out signs to whatever). I'm not sure it makes sense to go chicken/egg here: we can simply accept that people expect restriction policies to be enforced somehow, and they find totally reasonable that there is some kind of enforcement.

The whole business model of movies is based on restricted consumption; you pay more to get a better experience (e.g.: more quality) or less restrictions (e.g.: buy instead of rent). You can't expect this to continue to exist without a technical enforcement, and at the same time you can't expect Hollywood to come up with a radically different business model for a mature industry. You need disruption to arrive from somewhere else.

IMO, fighting against DRM for movies is ignoring the big picture. There are absolutely zero possibility that you will be able to experience Hollywood digital movies without DRM, because people accept and DEMAND to be restricted in order to access to discounts. The only alternative that makes sense is to boycott Hollywood and finance an innovator that can setup an alternative movie industry not based on restricted consumption (and good luck with coming up with a workable, scalable business model; that would easily make you billionaire and it's thus quite hard to achieve).