These are the guys who I tend to think put the responsibility of being loved onto someone else and refuses to do anything to make themselves lovable to themselves.
Yes, they will always be alone if they don't break free of this idea that others are responsible to provide love. One has to find the things that is attractive and loveable about themselves and embrace that. If they can't find anything to be loved and attracted by, that's a them problem. Change yourself to be the type of person who will attract what you feel you need/want. If that doesn't work, look inward and see where you weren't being authentic, where you could change, where you want to change. That is part of what dating is about. To see what it might be like to be with a certain type of person. If it doesn't work out, eh, it doesn't, but now you know that may not be what you truly want or need.
Sitting there moping about how you aren't being loved won't get you love. Being proactive in your life and nurturing the parts of you worth being loved for and letting them grow will.
Nothing good ever grows in the dark.