I don't think that's true of Disney+ (or Peacock, ironically).
Netflix - Draw people in with Stranger Things and whatever binge drama or true crime documentary goes viral, but nothing to keep them around.
HBO - Draw people in with Game of Thrones, but nothing to keep them around.
Amazon - Draw people in with free 2-Day shipping, keep them around with free 2-Day shipping, doesn't matter what anyone watches.
Hulu - Attempt to be consistently good with FX content (The Bear, Reservation Dogs, Under the Banner of Heaven, Dopesick), but no major draw outside of The Handmaid's Tale, which has a super niche audience
Paramount+ - Pray that Taylor Sheridan can keep cranking out bangers
Peacock - Nothing to draw people in, but if they get some hits people will stick around to watch The Office and Parks & Rec for the thousandth time
Disney+ - Come for Mando, stay for the Library
Disney+ and Peacock don't need to spend on "sustainment" content, because they already have it. They need to spend on must-see blockbuster content that continues to bring people into the service. Once they're in, they're in. Churn should be much lower than most of these other services.