Can you have a look at my question about the Nuvistors in your linkI maybe wrong but I think Anthony Michaelson went to the Nuvsitor when the Trivistor became hard to get, in bulk, or the other way around.
From what I was told by a distributor, he’s known for loitering around military surplus auctions, where he can buy a pallet load of a part for next to nothing, then goes home and designs a specific number of editions using that part.
Cheers George