Bandai-Namco also operate a lot of their own game centers where Pokken machines are in Japan.
Why the characters reamined exclusive to arcades before now is probably simply because support for the Wii U as a software platform was rapidly winding down by the time that Pokken came out - Nintendo...
The Switch doesn't really have enough established base to be suitable for a main Pokémon game right now. It costs at least two to three times as much as 2/3DS you can buy right now, and despite Nintendo's efforts to increase production their goal is to sell 13,000,000 consoles by next April -...