A few observations: I went to Axpona last year. The 2017 event was held in the same hotel from 3 years ago (when you attended). There were quite a few HUGE rooms on the bottom floor (the MBL, KEF and Bang-Olufsen rooms for example). Any of those rooms would have fit the 30.1 just fine. Also (unlike your experience) the Martin Logan Neolith were being shown in another very large room located on one of the top floors. The big Sonus Farbers were in another very good size room. In other words, there were quite a few large rooms in the old hotel.
This year the event was moved to a larger and newer hotel. I saw many pictures of this year's event and read comments from attendees to the show. From the pictures and comments it seems clear that the new hotel is bigger and the rooms are better than years past.
Magnepan is going around the country demoing the 30.1. From pictures I can see that they are using dealers demo rooms that are smaller than any of the big Axpona 2017 rooms that I mentioned above. So, in my humble opinion, it looks as if someone at Magnepan dropped the ball in failing to book a large room for this event.