I've never heard it mentioned by anyone working at SpaceX or any commentators (bar this person, it seems).
You'd have to build an entire new stage0 system, for starters, even if you've built a new one for starship 2.0 as it wouldn't accomodate the larger fairing size.
Considering it took them roughly 2 years to develope Starship from scratch, even if that's the case, it would still be an order of magnitude lower cost than anything else, wouldn't it?
> For a relatively trivial fraction of the overall telescope budget, non-recurring engineering costs could weld together an expendable Starship variant (no TPS, no flaps, no landing legs) with a 15 meter diameter payload fairing. Almost overnight, endless gnashing of teeth about the relative mirror diameters of Luvoir or Habex, or the relative difficulty of performing coronography with a segmented, non circular mirror, go away.