VoLTE & Wi-Fi calling last update 8 months ago? You have the technology implemented already, so why

It’s a strategy used by all parent companies with their cheaper companies. While they have all for the most part adopted VoLTE, they keep some special features on the parent company to try to encourage customers to eventually upgrade. While I think that it is a bad strategy it seems to be widespread through the industry.
If fizz truly wants to be different, this is the sort of rule that they could break

Yes the technology exists. Fizz will add them in due time.

As described, we are on a "flanker" brand of Videotron. Just like the automobile sector.... Toyota/Lexus. You have to show some differentiators for those willing to pay premium price for premium features/service.