Patents can be pretty specific, and in the case of the Narrow-Wide, it may be that Shimano/Wolf Tooth either tweak their designs just enough to not violate SRAM's patent, or they pay a license fee to them. They might just be different enough to not be mired in legal stuff.

Why not more 1x in the pros? I dunno. For events like Koppenbergcross, I'd want all the gears made. But I'm mortal. [MENTION=364302]Doge[/MENTION], in case you're up for anecdotal, I'm running a wolf tooth ring and it's much better than the sugino track ring I was using....