I don't think light aviation will change in the next fifty years any more than it has in the last 80 years. There will always be incremental change, but in the absence of totalitarian government it won't stop people operating what they want. I think you'll find what they want in 30 years won't be all that different from what they want now.
Friends are finishing up a Cub restoration at the moment, and I bet when I'm on my last legs and hanging around the airport, they'll be somebody finishing up a Cub restoration and flying a biplane, as well as experimenting. New stuff will occur as extensions of current efforts (electric etc) and as unforeseen technologies develop, but I think the endless 'the world is ending and must change radically' drum beat is a little ridiculous.
Neither of my airframes has been 'supported' by a manufacturer for decades, and I doubt that will change either! I'd also guess that classic cars and the like will be even more popular than they've already become, as new stuff becomes progressively less amenable to owner maintenance. It wouldn't surprise me if we see some of that rub off on aviation, as people feel an increasing distance from their modern possessions and a greater emotional need to connect their hands and minds with something, anything...