It could be 5-7 years for 100 dollars but, who knows considering how fast things can actually happen once they happen. I wouldn't sell very much at 10, just enough to make some space to make it to 20 and sell just enough to make some space to 50.... you get the idea.
Or maybe cycle up to Mount Everest, haven't heard of anyone doing that, yet." :D
I am pretty sure you get an, "I cycled up Everest and all I got was this shirt" shirt.
Retiring at 25... hmm... not too bad.
Also, the magnitude in which the price increase happens might influence – me at least – to sell bit more, because as the past has taught (even though past events don't definitely predict future events yada yada), is that big spikes tend to come down, for some time at least.
If it was the only shirt existing, I'd do it. Though I think there would be some imposers. Maybe I should blockchain the t-shirt and thus proof its authenticity as the t-shirt.