Assuming both Xbox4 and PS5 release November 2019, that would give the Switch a 2.5 year lead in hardware sales.
If the Scorpio gets turned into Xbox4 and is released March 2018, that only gives the Switch a 1 year lead in hardware sales.
How big that lead is really depends when PS5 and Xbox4 launch, which we have almost no information on at this point.
I will guess Switch will sell ~80M Lifetime between all form factor SKUs, revisions, etc.
Whether that takes 7, 8, or 9 years to do so, I do not know.
How many will have sold by the time Xbox4 and PS5 launch also depends largely on when those systems launch.
Either way, the launch of the Switch is less than a month away, and we will know more as these things all become history. Enjoy your life, gaming time, and friends along the way.
