If he did all of that, he would undoubtedly be the best LHW of this era, and I think you could reasonably view him as a Top 15-20 LHW.
The whole topic is a moot point. Bivol is not beating Beterbiev. Beterbiev will unify at 175lbs and move to Cruiserweight and grab a belt there before retiring. He is the real and true ATG people are talking about.
He will already be remembered as the guy that schooled Canelo. No matter what happens to him from here on out, he will always at least be remembered for that.
That is a good point - and both fighters (Bivol and Beterbiev) are not doing themselves any favours by not having that fight; just like Spence and Crawford, they elevate each other by having it - especially if it involves a FOTY close decision then rematch type affair. To be fair to Artur though, he at least has The Nail - both Bivol and Beterbiev could have done with having Kovalev on their resume. Too many hypotheticals and unanswereed questions in the LHW division