Nicotine will always exist and be available as will PG,VG, cotton, types of wire and batteries.
I don't doubt that nicotine will always exist.
However, I don't think the "and be available" part of that (if true in the longrun at all), will be anything like it is now. IMO, if it IS available...it'll be much more expensive, then also taxed to the maximum allowed by law, and probably not for sale at all to the everyday person or DIYer like it is now.
In case I'm right, I'm prepared and have nothing to worry about, regarding any escalation in cost, taxation, or imposed restrictions on buying it. If I'm wrong, I'll simply be well-prepared and will have most likely saved a bunch of money by buying it when it was readily available for $40-50 per Liter. Either way, it's a win-win situation for me personally.