Yes, but lets not forget Netero was far from his prime and his hatsu was not the most suitable to take down a tank like Meruem. A conjurer, manipulator or specialist of the caliber of Netero would certainly be able to beat Meruem. He literally died to poison. There are quite a few abilities that could take him down. Nen isn't only about aura quantity and tankiness.
Netero stated that he was half as strong as prime, this was betore going to train in the mountains to shape up. Say he gained another 60%.
With 60% of his prime power he got low diffed. Maybe mid diffed. In his prime he would push newborn Meruem to what a high diff?
Anyone can beat Meruem provided they have the right ability,etc thats what the manga taught us.
You can be the apex of every stat possible and yet still die to some stupid hax Hatsu or just a nuke.
Nen isnt aura quantity and physical stats I agree but when it gets to a point where the guy can blitz you before you ever react (Post Rose Meruem could literally teleport) its gets silly. Youd need insane reaction speed and for Meruem to be fucking around for your hax to work. Or once again just nuke him.
Netero only survived that long and wasnt a negg diff because Meruem wasnt trying to kill him ( he removed his leg in the first hit when he couldvr gone for the head) and because he had the perfect ability to stall him, so even people on Neteros caliber are kind of fodder to Meruem.