I would agree with RobertK.
In fact, I did some simulations using the INSCYD software (which has been discussed in the VLaMax thread to see what sort of VO2max would be required to get a 5.0 W/kg, with the assumption that we can get VLaMax down to 0.3 mmol/l/s.
I chose 0.3 because this is on the very low end of where you can get it (which is good for a high FTP!), but it is feasible. Many good age-groupers in TT and triathlon would fall around this region, and pretty much any good professional long distance triathlete and even GC contenders as well.
So with VLaMax fixed at 0.3, I found that 70 ml/min/kg was the exact VO2max needed to get FTP to 5.0 W/kg. Since VO2max and FTP here is normalised to weight, this applies to any weight - but of course reaching a high relative VO2max also requires that dietary discipline and weight-focus mentioned already.
And naturally, if VLaMax is any higher than the “ideal” 0.3, that also means that a higher VO2max is needed to get to 5.0 W/kg at FTP. For example, with a VLaMax of 0.5 (a typical Classics rider profile) the VO2max required would be 76 ml/min/kg.