I hate this line of thought with a passion. So if your talent happens to be musical you're only hope for a remotely related career is to be a loss leader for niche retail?
Plus if you're just taking stock shirt and putting your bands name on them then you're little better than a pan handler begging for money. People are only buying your outrageously priced shirts to keep you playing music. Why can't we just pay artists for their contribution to society instead of "pretend buying" their overpriced t-shirts?
There are lots of ways that artists could hypothetically be compensated and things will probably change a lot over the next 5-10 years. Right now, though, pretend buying overpriced t-shirts is one way to get money to musicians without going to concerts. Free idea for musicians: I'd pay to subscribe to webcasts of practice sessions.
But most people have no need for dozens of over priced low quality t-shirt with some amateur graphic design scrawled all over it. Sure I could buy them to throw away simply as a round about way to donate money, but there must be a better business model out there.
Puts a lot of burden on the consumer. Background checks; does this artist the potential to deliver good music again? Does the album's concept sound good? Which of the dozens of artists I know are asking for funding? (Not even to think about discovery) Also brings us back to the model of paying for a whole album rather than just the good parts of it.
I have backed exactly one kickstarter project (I think $50) and it was more email friction than all my iTunes purchases combined (maybe $1000?).
Buy t-shirts, etc