@bythewell - I wouldn't worry too much. There are definitely courses out there that people can take on how to repair shoes and how to make new ones. If you look online you can find quite a few people making shoes to sell and many of them will offer to fix the shoe once it wears out.
I think it's a shame that people buy cheap shoes so often now, but I can see why. I don't think it's cheaper in the long run to get more expensive shoes. It might be better for the environment and more comfortable for your feet though.