The Switch selling well is great and all but are we forgetting the Wii? For four years straight it trounced the competition but what did it have to show for itself? If you think I am simply talking about the failure of the Wii U or the fact that it's sales fell of a cliff in the fifth year then you'd be wrong. Off course there is still the chance that it may happen, nobody ever saw it so with the Wii because it was supposed to change gaming.
Instead I am talking about the fact that a Nintendo platform selling is only good for Nintendo. Third-party sales are still nowhere to be seen. Yes there are some token titles thrown at the system, usually beyond compromise, and yes the fanbase will eat them up. But ultimate third-party has little presence on the system and that means that the told number of units sold will remain meaningless. If we go by that logic, we can not only add up Sony + MS sales, but also the base console sales too! The base PS4 is still leaps and bounds more powerful than the Switch and the ports that the Sony system will get at least are competitive (I mean that both literally too, check out Apex Legends if you don't believe me).
Tell that to Capcom, Square, Koei, Marvelous, NIS or any 3rd party studio who put their games on Switch, they keep making/porting games to Switch. And why did you combine MS + Sony vs Nintendo? Or you're afraid that either of them wouldn't be strong enough to face Switch alone? Besides, Sony and MS can never be the same side, MS + Nin vs Sony sound more convincing.