This is a gross oversimplification. Most notably, Disney’s uniquely awful tangle of reservation systems such as LL heavily incentivizes the company to build and promote a very specific type of attraction to the detriment of any others.
You also fail to account for how Disney is very capable of driving guests in the direction they desire - they don’t WANT guests on RoA or Muppets because those attractions aren’t tied to their money-generating reservation system, so both are downplayed and even hidden. Muppets recently had its entire area aggressively redesigned and redecorated to make it LESS eye-catching and to emphasize the attraction LESS.
The time element is also key - both doomed attractions are very, very time-consuming by modern Disney standards, with Tom Sawyer Island in particular designed to entertain guests for hours. Disney doesn’t want guests entertained for hours or even for Muppets’ 20 minutes, they want them in shops or restaurants or spending money to acquire a LL reservation for the next sub-2-minute attraction.