So....people will spend more money during a day at Blizzard Beach than at the resort itself or....a shopping and dining district? You must buy a lot more towels and sand buckets than we do.
Rooms already don't have to be ready until 4pm. Housekeeping staff works 8-5 schedules per the CBA, with incentives to leave early if their assigned rooms are completed. This will undoubtedly reduce requests for early room access, but it doesn't change the staffing needs to prep the rooms.
This is such a cynically bonkers take. People complain that Disney doesn't offer enough on-site perks. And then when they announce a pretty dramatic new perk, so much effort goes into looking for ways to undermine it.