That is movie industry's fault, mainly exhibitors. I work on a VOD service and we are not allowed to upload the majority of films until a few months past the theater premiere. Every now and then we do a simultaneous release along theaters and even dvd/bluray, but thats not the standard.
As far as they can be. However, the right holders for movies are more paranoid about things than for music. So Netflix only works on some authorised platforms and has lots of DRM wrapping everything. Whereas Spotify have a bit more of a listen how you like as long as you stick to the basic premise that you pay by the month and actually treat it as subscription service model.