I don't have exact statistics, but much of the printing done at minilabs, even from digital cameras, is on RA-4 color paper. I don't know what the trends are in terms of what new minilabs (and bigger operations, for that matter) are buying, but I'd be surprised if RA-4 printing took a nose dive in the immediate future. AFAIK, it's possible for darkroom users to use RA-4 materials intended for minilabs, although if paper started to become available only in rolls you'd need to hand cut it, which would be a minor nuisance. The bottom line: RA-4 could well outlast C-41, since RA-4 can be used for making prints from digital sources.
A bigger concern might be obtaining chemistry in small enough quantities that it won't all go bad before you can use it. There are threads on APUG on this topic, although I don't have any pointers. There are several mail-order sources in the US, but I can't offer advice for you across the pond. In a worst-case scenario you might need to get chummy with some minilab operators and piggyback an order for chemicals with their orders.