It'll come down to one thing.
Does low power WiFi cost less (or will it cost less) per unit used than current bluetooth?
If I want high speed wireless comms that bluetooth can't do, I'll use WiFi as-is.
If I want connectivity that bluetooth can't do, I'll use WiFi as-is.
In other words, if it ain't cheaper, I'm not interested.
And I'm willing to hedge a bet that few others would be too.