[mmagin]

I think something which hugely benefited the appearance of Nixie tubes in hobbyist use was the incredible supply of surplus electronic components (frequently industrial / military grade parts) from the former Soviet Union that have become available through eBay over the past two decades.

Furthermore, whether due to reasons of preparation nuclear war (EMP) or due to relatively poorer expertise at manufacturing semiconductors as compared to the west, there's a huge amount of rather recent (1970s-1980s) tube-era parts. (The avionics of the MiG-25 are mostly tube-based, as I understand it.)