I'm not sure if it's a blackpill or a redpill, but the truth is, no man really wants a girlfriend. Men want sex.
The bullshit that comes from having a girlfriend (specifically, having to do things you don't want to do because she does want to do them) - no man actually desires that. No man wants to go to her parents' house. No man wants to hang with her friends. No man wants "dinner parties" the way women envision them. We just want sex.
...but for generations, men put up with that bullshit in order to get sex. Putting up with that was the price of sex.
But today, with hypergamy practiced without restraint, the only men who get sex are chads, and they can get sex from multiple women, so why would they put up with all that bullshit?? If Stacey A wont fuck-on-demand and then get the hell out, Stacey B, C, D, E, and F are all just waiting their turn. As a result, Stacey A plays ball with chad. Then later she'll complain that there are no good men who treat women well.
So the answer to OPs question is: if you can get a girlfriend, then you shouldn't get one. If you're attractive and women are willing to fuck you, then multiple women will be willing to fuck and you don't need to give anything in return. Frankly, the desire for a girlfriend signals to women that you're not a chad.