How long is a while? One year, three, five, twenty? There are so many factors involved other than skill. There is a great deal of talk about skill levels and being well matched, about how carefully we dress, and how we behave but, in my experience at least, most of those are secondary factors. A great deal has to do with your local community -- where you dance (what city), the size of your local community (200 people, 500, 1000, more?), the frequency of milongas, your frequency of attendance, the regularity of attendance (core groups of dancers, an ever-changing roster of dancers, a mix?), and so on. If you live in Buenos Aires, that's one thing, and skill or regularity might be the determining factor, but if you're in a big city in North America, then the local mores will apply (even though everyone pays lip service to the traditional codigos). Becoming a regular helps, but isn't a guarantee unless you can develop a pool of dancers who enjoy dancing with you. It sounds like you're doing all the right things -- dress, attitude, etc. -- so it may just be a function of people not knowing you. Don't be too hard on yourself. Go out more often if you can. Don't have any expectations. Enjoy the music. Socialize whenever possible. And things may change.