Oh goody. I've been on both sides of this.

I stopped speaking to my best friend of 10+ years because she never contributed to the conversation. I was always the one who contacted her. I always asked her questions. What did she do? She gave short one sentence answers and never asked me a damn thing about my life. Then it reduced to Happy Birthday and occasional season's greetings. The last time we spoke, she got angry because I suddenly reappeared, asking her a lot of questions which made her feel interrogated. The part that made me most angry was when she said I never told her anything about my life. Really? This person in the last 5 years of our friendship had a lot of issues, but did it never occur to her that if she wanted to know something, she should ask? It made me realize how one-sided everything was and I haven't contacted her since.

I've had this done to me. She snapped and stopped speaking to me because I didn't greet her the way she expected. She took personal offense to this, but eventually we made up and had an on/off friendship over the years. The last time I let her feel close to me, she humiliated me at her wedding, and proceeded to stand me up on three separate occasions. She has a lot of personal issues to work out so I can't be that mad. She has never offered a sincere apology, which is fine because we can be the kind of people who have a great time together but she needs to get her shit together.

There might be a few others, but these are the two that stand out. I think you're overthinking things, which means that you still care about her on some level. You can either try to salvage the friendship or just delete the text.

If you want to find out why, I doubt you will get an honest answer. She didn't offer one when you asked for it years ago and she isn't offering one now. If you want to be friends again...well, people usually change after a baby. You might have already adjusted really well to not having her in your life anyway.