He and his teams seem to have been quite successful with other businesses and ideas that were within the limits of known technology: electric cars and orbital rockets and LEO communications satellites. All of these things existed before (and all credit to the mountains of hard work of SpaceX and Tesla for polishing and improving them as much as they have).

Perhaps he’s not pushing the envelope enough if they haven’t attempted the actually impossible yet.

I’ll be cheering for them in any case; the impossible has a pesky habit of becoming possible in the decades that building some of this stuff takes. There is no shame in trying to do the impossible and failing; proving the current impossibility of hard things has value.