I think that those are all good theories.

Dated: Yes, the first four seasons are definitely dated. They went from "Scare Your Pants Off" (Goosebumps) to "Vegemorphs" (Animorphs) to "Henry Skreever" (Harry Potter). And not surprisingly, Henry Skreever lasted the longest. Then we go from "Bionic Bunny" (Superman) to "Dark Bunny" (Batman). Have you noticed that in the newer episodes the kids rarely bring up Bionic Bunny? The latest episodes I can remember Bionic Bunny being in were season 11's "Buster Gets Real" and season 12's "Do You Believe in Magic?" And about the technology thing, in the 90s and early 00s I would have thought that the Frenskys would have been to poor to afford internet access.

Voice inconsistencies: Brain and Timmy Tibble during seasons 3 and 4, and Sue Ellen would be especially confusing. 

Character continuity: I don't like it when characters are inconsistent, and I notice contradictions for at least one character each season, but I must agree that the characters' personalities would have the most dramatic impact for younger viewers.

Nostalgia: Then why haven't they released the early seasons of Arthur on DVD yet? I know that there were a bunch of VHSs with at least two episodes on them, and I think that they only went up to season 4.