Oh no, most people in my experience won't say such a thing directly. Many people have a strong aversion to conflict.

They will not say "you're too demanding for me" or "I can't deal with this right now" or "I really just want to do fun stuff" or whatever their reasoning may be when they can simply not take a phone call or 'forget' about a meeting or delay replying to an email indefinitely.

And again, regardless of her thought process, the reality is still the same-
you and she have an established pattern of her not being there often when you want her to and having hurt feelings around it.

I don't think it's likely she'll change, and I'm not criticizing either of you, just saying... that might just be the way things are.

She may feel more pressure to reply now however, so... by sharing your feelings I think you did increase the likelihood of some type of communication from her about your relationship.