I'd guess the future is bright for Maxi and even smaller scoots.
I got my first Silverwing about 2003 or so. The first few years there was a lot of guys thinking "that's not a real bike" and the scoots weren't really accepted on rides on such. I'd say somewhere around 2008-2010 I began to get a lot of questions from other riders. How fast will it go? Is it comfortafortable? etc. and comments like "maybe someday when I get old".
About the last couple of years I hear more and more guys saying they are tired of all the shifting or lack of storage of bikes and they really want to get into scooters.
I see this continuing. The more scooters that are on the road, the more acceptable they become. The more acceptable they become, the more folks buy them....on and on.
As long as I'm buying/selling bikes/scooters, I'll never die.