I don't think the hobby is big enough to sustain such events twice a year. Roland, Marge, and the astro-physics team are there; Scott Losmandy is there; Scott Roberts is there; a whole bunch of people are there that you may not recognize but have seen on the net or in an astro-mag. I don't see them doing it twice. And with total expenditures in recreational astronomy around $100 to $200 million a year there isn't a lot of margin to send a lot of people hither and yon. ….
They 'all' (mostly) do show up at the similar show in London, UK..... despite the fact that some Euro's do fly over to attend NEAF.
There have been attempts to do "NEAF West" and in the Southwest - all failed - because either the vendors didn't show up or the people didn't show up.
NEAF has become the annual "World Trade Show for Astro" - and that is unlikely to change.