Well said!
MK is in desperate need of a land-sized expansion (or two), both for capacity/crowd-flow and because MK is the park that will for the foreseeable future be typecast by the public as Disney's flagship (and thus should be top-notch/cutting-edge to hold its own against Epic Universe).
Tron makes the Storybook Circus / Speedway area more difficult to develop, but not impossible. They can get creative with rock work, etc. The Fantasy Springs area at TDS offers some illustrations of what can be creatively accomplished in a weirdly-shaped space with various sightline issues... and hey, the theme fits, too...
Some areas west of Adventureland, and across the top of Rivers of America à la Galaxy's Edge at Disneyland, are also serious contenders for being almost-as-good expansion plots.
So, there's a lot of opportunity still, but, to your point, Disney sure does shoot itself in the foot by sacrificing the long-term in favor of easy short-term development...