I had totally forgotten about it but we have a guy like that here in Bristol. In fact, I used to work with him before we both retired.
What reminded me was seeing a boy pushing his bike with a broken and very rusty chain as I did a slow loop through town. I slowed to chat briefly and he told me he was on his way to the bike guy. "You mean Mario", I asked? "Yeah, that's him". Fixing bikes is an excellent way to do useful work during retirement.