I mean, you would hope so. But honestly, do you think that's actually likely? Or is it more likely that they'd fill in the RoA and use that land instead? I think the latter is far more likely.
The RoA and shoreline surrounding it within the railroad berm is signfiicantly larger than the entirety of DCA's Cars Land. And the MK variant is not a clone of that land. They aren't building the accompanying town, which reduces that land's footprint by more than a third, and the Cars attraction shown at the presentation is also not a clone of RSR. The rockwork is much smaller than the Cadillac Range and I suspect the track layout is also not going to take up as much land either. If the art ends up being at all accurate, there's also a centralized "mesa" structure that the ride spirals up into. You can also see Big Thunder in the background of this piece of art to the left-
I wouldn't be surprised if this tall mesa structure goes roughly where the southern part of TSI was located, with the entirety of the RoA filled in and the lower half replaced with this Cars Land. Further up north being villains, but still potentially staying within the berm of the railroad track.
Something like this seems the most plausible to me, and wouldn't require as much land redevelopment as an actual expansion would-
View attachment 808189
The Yellow and Purple could be slightly larger or smaller depending on which land needs more space, blue being any potential spillover that might be necessary (but perhaps not needed as there's ample room within the existing RoA footprint if they do fill that in completely).
This is assuming however that Villains is still intended to go in the Frontierland area at all. They didn't actually specify whether this was still the plan to be fair. I still expect it to be, but they only said "coming to Magic Kingdom". There's actually still quite a bit of designated expansion land in Fantasyland. A plot directly to the north of Tron past the Circus. They could also probably figure something out with the land north of Magic Kingdom Dr if they tried (that blue highlighted area is a part of that).