I don't have the knowledge of chemistry to say anything about Renapur. From using it, though, I have found it useful in softening and conditioning a couple of pairs of my shoes. I don't see my making anything like this, from scratch, anytime soon! Judging by comments on here, other people have also found it useful.
It seems to reinforce my (amateur) view that it's not so much what we put on our shoes; it is that we wear them and look after them. That is probably more than 90% of the male population does.