You're identifying one of the (many) underappreciated cost in the RLWE FHE stack. The evaluation key problem doesn't scale, and no amount of hardware acceleration fixes a per-user storage and loading overhead that grows with the security parameter.
I think one counterpoint here is that you can still get value in using FHE in settings that don't involve scaling the number of users (e.g. B2B, public/private collab).
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You're identifying one of the (many) underappreciated cost in the RLWE FHE stack. The evaluation key problem doesn't scale, and no amount of hardware acceleration fixes a per-user storage and loading overhead that grows with the security parameter.
I think one counterpoint here is that you can still get value in using FHE in settings that don't involve scaling the number of users (e.g. B2B, public/private collab).