If we accept the notion of Pareto principle and hypergamy that the red pill claims (and I do accept it is true). Women will always choose the most attractive males, and the top 20% will have 80% of the sex.

So TRP tells you: Improve yourself and get to the top 20% and you're golden. The problem is that mating is a zero sum game. If every male is going to self-improve himself at the same level everyone will be exactly in the same situation as before, with the only difference is that the men wasted time and resources while doing it. In game theory this situation is known as Iterative Prisoner Dilemma, or in this specific private case: Arms race.

A very simplified example would be a situation where 2 Men (Johnny and Mark) compete for the same woman (Lisa). Lisa prefers Mark but hasn't finally decided yet. Both of them decide to invest money in expensive clothes to improve their chances, both buy fancy Armani suits. And eventually, Lisa still prefers Mark. Their relative situation hasn't changed but they both lost money to buy those clothes which made them both worse. The thing is as soon as one of them decided to buy fancy clothes the other guy was forced to do the same in order to not lose his advantage. That's the classic prisoner dilemma result of rational players' choices that lead to negative results for both of them.

But itself improvement is still a good thing - even if their relative situation didn't change they still got benefit from doing what TRP suggests

I would agree with this notion for some of the things TRP preaches: showering and basic grooming are almost always good. But a lot of the things that TRP preaches doesn't really make you a better person, It just makes you better seducer:

  • Lifting is good for you, But what if you would rather do yoga or other kinds of sport that doesn't build as impressive physique. It will put you at a detriment compared to the gym bros.
  • There is nothing inherently good at being good at flirting or learning the ability to approach women in public spaces.
  • There is nothing inherently good at having a better fashion sense, eventually you will be forced to spend more money/time to outcompete other guys in your ability to dress.
  • There is nothing inherently good in choosing high-status hobbies and lifestyle over choosing low-status hobbies and lifestyle (Playing in a band Vs playing chess)
  • There is nothing inherently good at having a cool and polished social media account and wasting time on signaling with cool travel photos and status symbols.
  • And there's nothing inherently good in doing plastical surgeries or lookmaxing.

Many of the things that TRP calls self-improvement isn't actually self-improvement but weaponized signaling that doesn't make you a better person for society but just a better seducer. So in order to keep up with the competition - Men will have to spend more time doing things that make them attractive instead of doing other valuable things like volunteering, becoming more educated or investing time in low-status hobbies that they will actually enjoy.

And eventually the situation of men as a whole wouldn't improve (Maybe some men would getter a higher ranking after focusing on TRP advice, but on average the same amount of sex will happen). TRP just makes this process of competition more obvious and more efficient and the competition more fierce, Means you'll have to waste more time and resources than before to compete.