Thanks to Moore's Law, functional programming is no longer just for the mainframe, but can now be used for normal programs on standard platforms. If more people choose functional now just because they like the style[1], then it could be that procedural would be becoming less fashionable[2] over time.
[1] instead of before, when "wearing the hair shirt" of functional programming could be seen as declaring oneself a strong enough hacker that one could hack despite all the practical drawbacks.
(compare "Honest Costly Signal" in the context of https://news.ycombinator.com/item?id=23570975 )
[2] in the mass fashion vs class fashion sense.
(compare https://news.ycombinator.com/item?id=23560291 . I doubt it's controversial to say functional has always been on the Joycean side.)
The con argument: we have enough memory and cpu now that functional languages are more practical than they ever were, which may help them be more prêt-à-porter fashion than the haute couture of a geekish peacock tail or springbok leap.
[1] I'm usually asking questions about long-dead endian-style controversies (cue the compromise of arrays starting at 0,5), and it's been nice to hear many of the people involved recommending the work of their opposites. Folk history seems to ascribe more dogmatic attitudes to the people who lived through technical controversies than they actually have.
Another lesson learned: when I try to tease out chains of influences, a not uncommon response is "I wish I'd been that clever, really it was just hacked together."