This is true to a degree. It's important to remember though that this transition is basically de-valuing entertainment everywhere all at once. Disney+ has been phenomenal in the sense that it is surviving and thriving when other streamers are struggling, but the end result of having so many streamers is that content is more widely available and for far cheaper than it was before. On top of streamers for all the big-budget content, YouTube and TikTok are still flooding the market with near-free-to-produce content that is competing for the same eye-time as everyone else. Add in twitch and the video game live play market, and you see a big squeeze in entertainment as a whole.
This is why the industry is struggling as a whole, not just Disney.