Pokken didn't out sell SFV. I think the correct buzzwords you're looking for is "Pokken outsold street fighter on one weekend in Japan" because that's where that bs came from. Pokken isn't even north of 1 mil and SFV is over 2 mil shipped.
Also I don't doubt Tekken 7 will come to switch, because Namco likes wasting money on Nintendo products early. No one is going to buy Tekken 7 on the Switch, or the Xbox One for that matter. With no cross platform play every version but the PS4 will be dead in a month.