I imagine that would take months at least. Meanwhile, only a selected few get to have access to what might be some of the most significant developments in mathematics. That seems incredibly unfair.
And I do not buy that it is “unfair” either. That argument proves far too much - it would equally apply to peer review, editing, revising, publication, and indeed any non-essential activity by the author from the moment of their epiphany onward.
Note also that my suggestion is something I came up with on the spot in a handful of seconds for a field I am entirely unfamiliar with. It should be trivial in the extreme for a well-compensated and motivated professional familiar with the field to take a few weeks and vastly improve on it.