From the perspective of an individual man, it's pretty much impossible to argue against MGTOW. Men are better off going their own way than marrying or cohabitating.

The only valid counter argument in my opinion is that MGTOW is not a viable lifestyle for the majority of men in the long-term. Not if you want to maintain civilization anyway.

Infrastructure: If there's not enough men around, or people in general even, infrastructure will fall into disrepair. Roads, telecommunications networks, power grids etc.

Science: A lack of men also means humanity has less collective IQ and scientific advancements will slow down and eventually we might even regress technologically.

Security: Security might actually improve internally in some ways with an aging and shrinking population, but if there are any external threats then the risks will increase if there's not enough men of military age.

Economy: In terms of the economy, for growth you need both producers AND consumers. Even rich MGTOW men rely on beta males and the females who spend their money to make bank. If everybody just works and saves money, then the velocity of money will be reduced and the economy will shrink.

All of that being said, obviously I will not "man up and marry that hoe" just because "muh duty" to save Western civilization. Not going to fall on my sword. The deal for men has to get A LOT better in this society.