management bandwidthThere is no management.
After the handover (which would be needed for a sale as well) there is no need to ever talk again. Just put the guy on auto-pay and have the contract automatically terminate when the revenue falls below a defined threshold (i.e. the site has fizzled out) or when the SLA is not met. Not rocket science really, should take all of 15 minutes to write a shell-script to send out the notification when it happens.
Of course if you pick the wrong person you might have to do it again, but I'd hope 37s would be able to gauge the competency of a candidate for that role. It doesn't take a genius to keep a trivial rails-site running, and motivation shouldn't be an issue with that kind of compensation.
But sure, if throwing away $100k/year in passive income better "aligns with your values" then you have bigger problems anyway...