They were probably interested in your profile but lost interest once you two started talking; they realized you were not a match. Since it was only a series of texts, they just stopped talking to you once they realized that. People just don't say "hey, I'm no longer interested in you" on online dating sites, before ever even meeting in person. It's awkward and confrontational, and they haven't invested anything in you yet. They are probably afraid of hurting your feelings or they don't want to have to deal with you asking "why?" Plus, people are usually talking to multiple people at once-- it would be time consuming to bother telling every single person "hey, I'm not interested in you." Don't worry about the guys who are not interested. It's not worth your time.

What do you have going on in your life other than online dating? You seem sooo focused on dating right now. It may be worth exploring other areas of your life and putting more attention there: career, family, friends, hobbies.