If the insurance company is really on the hook for 420 million, there are probably some interesting discussion going on right now about a cheaper robotic repair mission or so.
A crewed mission won't happen because of cost and physics reasons, but it would be cool to see a Falcon Heavy launch a stripped down Dragon with two crew and a kick stage for a GEO servicing mission.
I think you're right that a dedicated Falcon launch would be needed for getting something like a Northrop's MEV out there, but if the spacecraft was "only" a smallsat with a few commercial arms on board, that might fit on a SpaceX rideshare for a lot less money.
I was picturing something boosting itself (or riding a tug) from a rideshare dropoff in LEO. The Transporter missions have all been to SSO, though, so that isn't super helpful.