Maybe because of the brand equity and the recall. When you say Pearl, you have Dennis Chambers, Slipknot (JJ), RHCP (Chad), Kiss (Singer), Omar Hakim.
With Tama you have... my personal recall, only Metallica (Lars). That's pretty much it. Portnoy mayb but he's more famous for his signature cymbals (Max Stax) than his drums.
To be honest, I'd also pick up a Pearl instead of a Tama only because I'm more familiar with the brand.