Women are attractive by default. But they can't do much to improve their given attractiveness, beyond makeup/surgery/clothes. Most men are by default unattractive. But on the flipside, through gargantuan efforts, they can build up their attractiveness through decades of effort, if they don't fail.

Even the ugliest woman will have more dating success compared to even just a below average man. But the men are still in a better position, if they have the willpower to work for many years. (and avoid failure or things like depression)

For 90% of men, increasing their attractiveness would mean things like making a lot of money, increasing their social status etc...

Socio-economic status is a huge part of a man's attraction. You can also go to the gym and whatnot, but even if you get really buff, that won't do much if you're ugly. Most of a man's attraction comes from socio-economic factors.

Now, socio-economic factors are much harder to improve. There isn't anything harder than making money or becoming somebody. But that's just how natural selection works. Cruel, but that's just how life is.

Granted, a man born handsome will almost always be much more attractive than the ugly guy who worked his way to riches and status, but that's just life, better genes have it easy unfortunately, it applies to women too.

And that's the difference between men and women. Women have it easy but they can't improve much. Men have nothing but they can improve a whole lot if they work hard for years.