I know I said I wasn't going to take us in circles... but bear with me!
I think the “back burner” sentiment would come from the sense that, for whatever money has been spent at USF, Universal has prioritized
other places (IOA, Epic) for the ambitious projects, as well as the fact that two huge projects once rumored for USF -- Nintendo and Pokemon -- were/are being shifted to those other parks.
And along the way, there have been a couple other inflection points where they chose a more budget-friendly option instead of trying to get a jump-start on a course-correction (they could have added a dark ride as part of the DreamWorks plan, they could have built a dark ride --
or almost anything else -- instead of VillainCon, etc.).