Actually, no, it's not.
Not if you compare exact vehicles and levels of service. Realize, Minnie Van is equal to XL
Example (only using Uber as only Uber will offer a car seat option)
UberXL+Car Seat (only 1) from Pop to CR, $25 before tip
Uber XL, without car seat, from Pop to CR, $17 before tip
So, depending on where you are going, a $20 ride, which includes tip, was not at all out of line, and $25 isn't all that high either. Plus, it gets you 2 car seats, something Uber can't do at all.
Now, for those who don't need XL and/or don't need a car seat, it's never been cost effective. A fun splurge for sure, we've done it several times ourselves. But it's also not a fair comparison as you can't compare the cost of X to XL
The only other thing you need to decide, and it doesn't have a monetary value exactly, is how much is a drop off at MK bus stop worth to you? This is the only other thing Minnie Van can do that Uber can't. Uber can get to CR but that's not the same as Bus stop 11