I've seen IBIS look like bad warp stabilizer. That's why I dislike it so much. When folks have a bad solution (IBIS), then tend to stop asking for the good solution (OIS) and just live with the flaws.
More like when folks have IBIS, they appreciate that it provides a benefit to the dozens of lenses without OIS that they already own and that already exist, and a solution like that in the GH5 also benefits by working with OIS in native lenses for even better stabilization so they also still want lenses with OIS. But we've already been through this bad argument of yours multiple times on this board.