Currently Online 
Technically, he's totally right, as every kind of activity is it's own niche of activity. That niche might be huge (see the Marvel Cinematic Universe for movies, for instance), but it's still a niche. Anything that isn't technically niche doesn't have it's own niche and is doomed to fail. Even a monopoly would technically be a niche - it just fills it up to 100%.
Console gaming is a huge niche worth many billions, so it's rare to be called a niche, but it's one nonetheless, just as is PC gaming, tabletop gaming or mobile gaming.
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/
