The Epcot Wind Down was at least paired with food/drink and catered to a specific target audience. To have rides open you need broad appeal and a decent number of ticket buys..
To give you an idea of "how many tickets?" one factoid that has stuck in my brain came from former WDI vet Eddie Sotto ages ago - it takes 10,000 paid park admissions to put Epcot in the black operationally. If there are less guests, it doesn't behoove them to open the doors.
MK operating for any length of time, though admittedly offset by the cost of operating for the normal day covering some of it in overlaps, has to be fairly high.
Making this a head scratcher as to how they plan to make it profitable.