Sorry, let me rephrase that - he does NOT only work as the owner of Blockland full time. If he is currently unable to get employment, I don't know - but I'm sure that he is looking for a job.
Blockland has what, 35k users now? That's very little money. He probably makes something close to $5 a sale (after taxes, and garagegames charges). That leaves him with 175k. Now, split that over the 5 years or so that Blockland's been retail (Since 2007, I think?) and you get a mere 35k per year. That's less than the average income in America (Something like 45k I think).
Logically, it's doubtful that he ONLY does Blockland.