Ah...we have to assume what is given by the show. I mean legit, it looks like no female even has a passing interest towards Mako. Good or bad, the series doesn't give us enough to work with for us to know he is some kind of chick magnet. But gives us enough to realize that he is awful at relationships. Plus somehow managed to mess up two relationships with some of the most powerful women in the series.
In Asami's case twice.
While I acknowledge you argument is super valid.
I argue that the reason you see none of this is because mako isn't an interesting character. Bolin is, thats why he is in relationships every 2 seconds. Mako literally wooed asami and korra by doing nothing. Like who actually cares, I only care enough to produce a joke argument. He's literally a nothing character, he is heroic, but thats it really. He's the fred of the LOK scooby doo. He probably was dating someone else in season 4. but is that even interesting enough to show, and would this person even be plot relevant at this point. Interesting chemistry and plot relevance are a thing here. Mako is a 2d image of a person, literally a metaphorically. And as we have learned in real life, not being interesting as long as you are attractive don't mean much to a lot of people.
These hypothetical relationships probably wont last that long, but to say he wont do aiigt for himself is silly. Dude did nothing, and got two of the most powerful women in the context of that show to be like i want his butt. Nothing, I don't think thats a fluke. I think that can be replicated, I think that happened to him already. But he just cares about his own shit more than their feelings. But he isn't an interesting enough dude, to even tell that story with less plot relevant characters.
Mako ain't gonna accomplish shit, won't be shit, ain't gonna do shit.
Fuck that cheater and his eyebrows.
Village did nothing but make me place him above Suyin Beifong on the "people who I wish would get hit by a truck list"
That guy that was mean to you one time is probably doing alright with his life. Its best to find your own happiness, they are going to find theirs.
I don't care if you hate mako, I don't even like mako. But to say he wont be nothing is silly, just because someone is mean to you or anyone else doesn't mean they wont accomplish anything. That's just naive and self centered.