Cryogenic distillation of air is a solved problem. There are plenty of plants already in operation all over the globe meaning there only needs to be modification to existing plants to further collect and crack the remaining 0.1% of air. I'm sure this is not hard to do with existing cryoplants.

If we already have the capacity then why are we without Neon production is a good question. Neon isn't in high demand like the easily extracted major components of air: nitrogen (78%), oxygen (21%), and argon (0.9%). Neon is something like 18ppm in air so a lot of energy has to go in to get very little out. So my guess is economics where the existing Ukrainian cryogenic plants have kept their prices low enough to discourage adding this capacity to new/existing plants elsewhere (maybe they get cheap energy, subsidies, etc). Now it might be profitable.