The long-term viability of film will depend ultimately on someone inventing a cost-effective way to manufacture it in smaller quantities.
A cost-effective way which allows a positive return on investment.
According to the PDN article, Kodak E-6 was no longer commercially viable, so it was discontinued, never to be seen again. I've read that it was 1% to 5% of their film production. The amount of chemicals used to make it had to be mostly wasted, as nothing was shared between E-6 and C-41/ECN processes. The C-41/ECN processes share chemicals, so there's some synergy there.
Lomography is growing, but at 2 million rolls in the last year (of rebranded non-Kodak film), I don't see how it's going to be a serious replacement or source if, say, Kodak reaches the point of non-viability. If Kodak loses, say, 75% of its motion picture footage sales, will that leave it in a position to still be viable? Or will the film division collapse, leaving Kodak with no profit?
It takes millions of dollars of investment and years of development to bring a modern film to market. So far, there's one ex-Kodak engineer in Australia who build a coating machine in his garage, from scrounged parts, and some new parts. Good B&W, but no color. AFAIK, nobody else has built a home coating machine. There are some basic materials that are problematic to purchase, like the base material for coating.
Currently x-ray film is plentiful and cheap, very cheap. But of course you have to shoot LF to take advantage of it, and it can be a problem to work with it.
So far, it appears that the best source in the realm of the established manufacturers. The old Agfa machines are still running, and Fuji's plant is much smaller than Kodak's plant.