Some guys really are always too busy to be in a relationship. Other guys use “I’m just too busy” as an excuse to avoid commitment.
In either case, they shouldn’t be leading you or any other woman on. If one of these busy guys is “talking to women like they’ll date them,” as you artfully put it, it means that he’s leading women on. And he’s probably doing it to have commitment-free sex.
You can’t change how men like this behave. So you have to just trust your instincts in dealing with them. If a guy tells you that he’s too busy for something serious, then a serious relationship probably isn’t going to happen. Either because he’s a lying his way into sex, or because he really is too busy.
There are plenty of men out there that have the time and the inclination to be in a relationship. I suggest letting your instincts lead you to them.