The future isn't .40 outside the sport, so I'm going out on a limb and say that the future isn't .40 inside the sport. Sure, the veterens/whales of the sport have their money in .40s, but they will retire from matches or slow down someday, their guns will get old, and the prevailing market for handguns (9mm) will win over. Why? Because the new shooters have 9mms, and when the USPSA guys are not shooting major scoring, they too are shooting 9mms most of the time.
Carry optics is popular because it's the only division where 9mm get to play with high round counts (unless you count open... and we know why that's prohibitive).
The fact that this topic keeps popping up just shows how much the tide is changing.
I think the sport will only get hamstringed by resisting the market forces at play. 9's outsell all else.