Would you call her a friend or an acquaintance; and, what do you think her view is regarding the relationship? Realise too that being a friend or acquaintance does not make you the priority in her life. Sounds like she as a great deal on her plate to occupy her. Yes it would be nice she was more available to you but that simply may not be possible in her life right now. Consider too that her idea of staying in touch may not match yours.

Yes, evaluate the relationship and what you consider are reasonable expectations of it. But also consider that which may be expected of yourself.

I wouldn't be rash.

Talk to her about your expectations before simply ending the friendship. Ask too what she expects of you.

As for the texting, perhaps that is not her ideal way of communicating. Personally I hate it and think it is impersonal. Try sticking to calling her instead.