Sheer size of the installbase? The Wii U installbase is bigger than the PS4's.
Err...what? The PS4 has sold over double what the Wii U has sold in about half the time worldwide.
And just because it's a JRPG doesn't mean that it'll sell better in Japan. I reckon Xenoblade X will sell better in the West, to be honest.
Baba also insisted Tales fans were on Vita and not 3DS after Tales of Innocence sold quite a bit worse than Tales of the Abyss.
Not that I necessarily disagree, just Baba and Tales are not the best example.
I don't think there's any better example than Baba and Tales, honestly. It's a mid-budget JRPG that's annualized to reap profits.