How is it not easy to understand? Seriously.
Let's say Splash is closing for more maintenance. That would be good. We all want more maintenance, even though it's a shame it has to come at the expense of the ride's operating hours.
But it
IS most definately about money. The cuts that have decimated the WDW maintenance over the years, as a cost-saving measure, are what has landed them in the position where they would need to cut EMH hours to get the needed work done. If they were working with a fully staffed and funded maintenance crew, there would be no need for the extra few hours each night. Rather than bring extra manpower to ensure the ride is properly maintained, even with the short turn-around on EMH nights, they just cut the ride from the lineup.
Splash is indeed a difficult attraction to operate and maintain, but with the proper funding and care, it can certainly be done and done well. Tokyo's version runs just as much as MK's, but with none of the show quality or maintenance issues, looking as good today as it did the day it opened. Why? They spend the money to make sure it is that way.