The entire point of playing a fighting game is to attempt to solve this problem. A good player, by necessity, can't be accurately predicted; if they could, they'd be a bad player.
Second, your rebuttal is not especially good support for the idea that we should be trying to solve the problem with a technology specifically designed to imitate humans.
The distribution of people who enjoy playing fighting games will probably look somewhat different, though.
ie: imagine a player running to a ledge spanning a gap. The "naive" interpolation would be they continue running and fall off the ledge and die. A smarter system would realize that almost all the times they've run to the edge of a ledge, they've jumped and the AI could jump for you and then later confirm that prediction was correct. They could even jump at the median of all of your previous jumping choices and then lerp your position over time so you land at the correct point based on your actual jump.
I assume the interpolation relates to something displayed on the screen? The idea makes me kind of uncomfortable, because it seems like it would confuse players by causing identical jumps to display different results. If you only learn about jumping by watching the departure point and the landing point, fine, but if part of how you get used to jumping is by watching the animation, this sounds like it could make things a lot harder.
(If the player sees position data calculated locally, and the interpolation is just a process for bringing the remote idea of where the player is into line with the local idea of where he is, that sounds much better.)
It's the equivalent of letting an AI take over the player when the player drops out, with the AI intended to replicate the dropped-player's playstyle until he rejoins. In short enough time-spans (disconnect-duration) you have some hope of being exactly correct.
And if you were 100% correct at predicting the remove player, all of the time, you don't even need the other player --- you could just run the AI and stay offline, and just "pretend" there's another player.