You say Nintendo will be 50 million units ahead at the start of gen 9, which is a completely nonsensical stance considering the Switch will not share a library (and by extension, target audience) with the consoles that will release in that timeframe.
Explain the relevance of the "gen 9" distinction you were trying to make, I guess.
the switch already doesn't share a target audience with ps4/xb1. people aren't buying switches to play live services and cinematic western games. they're playing value games (collections), retro and retro-style games, family games, and japanese games, with some western pc game crossover (doom, skyrim, diablo, fortnite, overwatch, etc).
people usually use generation as way to identify eras - not power, library, etc. the eighth generation was the generation where online multiplayer paywalls became standard, more integration with social media (share button on ps4, miiverse on wii u), the establishment of the mobile industry as its own mainstay (to the detriment of the traditional handheld market), and an overall and massive decline in hardware sales.
the ninth generation, so far, appears to be a bigger push towards streaming services and the idea of expanding the kinds of devices games can be played on. to that extent, microsoft got a start with gamepass, and sony introduced pc gaming into ps now, but this should be more integrated into future consoles from the start, especially as we see google making their move with stadia. the switch definitely fits into that as a piece of hardware, merging gaps that had previously been there
a generation prior with the wii u - a system with a tablet controller that couldn't be played far from the system, and the vita, a handheld that was supposed to provide console gaming on the go.