It really seems like Disney is overreaching here. First, they are increasing what has been a typical first release price to PURCHASE a digital download from $20 to $30. Second, they are converting this purchase price to a rental by requiring a Disney+ subscription to continue viewing the "purchase."
At least to me, the argument that the $30 cost is in line with going to the movies falls flat. I would pay a supermarket $45 for an uncooked filet mignon because that's what I might pay at a restaurant. Even for those of us with awesome home theater arrangements, going out to the movies is still an event, and that event is diminished when you self-supply the venue and the popcorn.