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.