MVP is without a doubt the best classic riders of this age but to strive for 5 it's better to be a climber/puncher that focusses on one day races than a classic rider that tries to become a better climber. If that makes any sence.
Lombardy will always be a climber race and classic riders stand little to no chance. Liège is a climber race to but because of flat finish classic riders stand a fair chance (such as WVA or MVP). Don't underestimate the RVV neither. It has more altitude meters than some mountain stages in grand tours.
Point & examples
- Gilbert: Puncher first with a refocuss on Northern classics towards the end of his carreer
- Valverde: top tier Valverde would have been perfect to try for all 5 if he wasn't focussed on winning Fleche Walloon like 29 times or so
- Superstars that are GC/climbers first such as Poggy, Merckx (and maybe Remco)
- bonus round Pidcock: I might be stretching a bit, but he has the profile to win all 5 monuments
Those are the profiles that could/can strive for 5 in their time. With eddy obviously having done it.
Regular classic riders such as MVP, WVA or more historic figures like Boonen, Museeuw, Cancellara are very good in Northern classics but lack the versatility (and climbing legs) to win more then RVV, PR and perhaps MSR. There's nothing wrong with that. I would rather watch MVP race CX in winter, RVV and PR in the spring, fool around in the TdF in July and aim for WC in September. That's enough right?