Possibly, but I don't think so. Wide range compact doubles will become the prominent choice for the road, but triples will still be strongly preferred by loaded touring riders and a small but persistent portion of recreational riders on road bikes. I don't see them going away as an option for MTBs anytime soon if ever. MTB doubles will be an increasingly popular choice, especially for performance oriented riders, but triples will continue to be a popular choice for many.

My guess is that Shimano will keep making triples for 105 and lower for a few years. The remaining road triple crowd may eventually be served by some version of a MTB triple.

If not, there will always be options from smaller companies.