They can't.
World of Color takes place in a
3.5 acre pool which is needed for the systems that raise and lower the fountain platforms.
The world showcase lagoon has a "natural bottom" and is classified in the state of Florida as a 38 acre private lake. It connects to a series of waterways that in turn connect to other man-made and natural water bodies across property and beyond.
(Disney calls itself home to the tributaries that start the fresh-water source of the Florida Everglades though a lot of places could make that claim)
While being man-made, part of the bottom is not entirely stable and it apparently has a maximum depth of over 14 feet.
Long story short, it's not like they can just drain it
(killing most of the natural life in it, in the process) pave it, and install that system which would need to be many times larger to cover the area.
I guess they could bring over the audio and build an entirely different show around that but who want's that sort of half-handed copy of anything?