People used to be very impressed by Netflix's infrastructure-- CDN boxes in major ISP sites, all the reliability engineering gimmicks. There was probably a case to be made that "IP first" companies wouldn't want to bet that big on trying to be tech firms.
There was also a secondary risk factor, especially at your B-tier IP firms. Disney owns everything and can presumably fill a viable streaming catalog, but if your catalog is a bunch of old sitcoms and movies-of-the-week that your acquired before people were savvy about rights negbotiation, that doesn't command $10 per month. On the other hand, it would do well with an established service, plumping its long tail offerings. I suppose that was the original premise of Hulu, collecting some of the catalogs that weren't big enough to self-sustain.