Cool little story. I really like speculative fiction like this.
The only part that is too far-fetched is "A lawnmower repair shop down the street builds these mowers and provides them for free.". Why would they build and provide them for free? Surely they would lease them to the local governance body using automatic, demand based bidding and negotiation.
Other than that, very cool. Though I fully expect these comments to be filled with people discussing how this future sounds terrible, entirely missing the point of the story (which was to speculate and discuss novel models of payment, ownership and reputation enabled by blockchains, not to provide an exhaustive exploration of possible futures enabled by blockchain technology).