Hmmm. Yes and no.
Sometimes I've had people disappear and then come back to me with sound reasons and we've carried on happily.
I think it's more a problem for me if I take the time to write out an introduction and all of that then someone simply ignores it and carries on role playing but doesn't offer me a word. If someone sees my introduction and is like, fuck no, fair enough. As long as someone tells me they're not interested or the introduction isn't their cup of tea, then it's all good. I just don't like not knowing, especially because I then think I have more active role plays than I really do. ;p
I think the most important thing is to find some dedicated partners, there are some out there, and stick to those. - As xanaphia said as well. Tends to help if you have some reliable partners.