Yea basically every part is replaceable. Even the fabric can be replaced separately of everything else. This is a really simple pattern to sew and sort of the secondary to my focus so far. So you could put on a thick one in the winter and thick in summer. You could also just chuck the fabric in the wash, no glues here.
Idea is that it's open source and anyone can access and modify patters as they would like. Do that for free, but could make business by selling fabric uppers, molded rubber parts, etc etc.