Switch could potentially make it in 2 years, but that's gonna be a very tough mark to reach, especially if the parts problem persists. So I'll say 2 years for an optimistic outlook and 3 years for a more "normal" outlook, and 4 years if the parts problem keeps Nintendo from producing enough units to beat XBO in 3 years.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454 List as Google Doc: https://docs.google.com/spreadsheets/d/1aW2hXQT1TheElVS7z-F3pP-7nbqdrDqWNTxl6JoJWBY/edit?usp=sharing
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/
Free Pc Games thread: https://gamrconnect.vgchartz.com/thread/248138/free-pc-games/1/