What term retirement usually denotes to is, to stop working. People often don't like job, so to retire usually tends to be on top of the list. However, if one likes what he does, he will do something similar to pass the time even after retirement.
This is true.
Someone who likes what he's been doing if it's a job or a hobby that makes him happy and earn money, he'll never retire to that. Who likes job? We all hate it when we're working on a job that we don't like but we have to go to office for our needs and salary.
But it's a different thing if it's about retirement, we all want to get out of the zone where we're always monitored by the company, scolded by the boss sometimes.
That's why those old people that don't retire but keep going on with their passion or hobby and fortunately, they're making money out of it, they don't see it as a job but just having fun and no word as retirement to them will be heard.