I suspect that more singing gigs will mean larger audiences....
OK, that gets me into An Ongoing Thought: instrumental jazz since bebop & economics wounded big bands critically has been chamber-music-with-drinks-&-conversation. When jazz left dancing, it left its audience. Now, that's just the way it is right now. So audience growth will come with more danceable music &/or more singing/emotion. We ain't gonna invent a 21st century jazz dance that I can see, so let's have more singing, feeling, emoting, etc., things that get to people's hearts. As much fun as it can be to sit back with a cognac in hand (in my case) & admire a band, I want to be moved by jazz, not just interested. Take heed, Wynton Marsalis...