Does Jimbo Wales have people appointed to answer comments on his talk page as him?

Probably. It wouldn't be very difficult to have a computer program that allows someone appointed for the purpose to leave Jimbo "autographs" on user talk pages but not edit anything else.

Also, the computer program could time out for when Jimbo is collecting his large speaker fees, so that no one can say that Jimbo "autographed" a user page at the same time he was at a podium without a computer.

And if by some careless mistake such an "autograph" were placed on the user talk page of a banned user, Jimbo could just use the Oversight function to undo that mistake. No harm done.

In effect, what you're asking is whether or not Jimbo Wales, who has full administrative rights on nearly all Wikimedia "projects" (the only exceptions being those that have specifically asked that he stop meddling in their affairs), routinely gives his password to one or more personal assistants who handle silly, trivial requests of this nature.

It's tempting to say that he might do this, and of course there's no way to know for certain. However, I consider this extremely unlikely - even if he could trust the employee(s) to not break up with whatever Canadian female TV journalist he's currently dating on his behalf, how could they know which users to deny these "autographs" to? If they accidentally did this for a banned user, imagine the devastating consequences!

Last but not least, it certainly isn't an autograph in any real sense of the term. It's possible to automate a physical signature, though - the machine for this is called an "autopen," You can even look it up on Wikipedia:

No, not yet. He grants those "autograph" requests only once in a while, so it has not become necessary to appoint someone to take care of all those.