Mom is mad I'm moving away. I don't care.

My mom is mad I'm moving to another nearby city. It's literally only 30 minutes away and she's behaving as if I'm moving to another state. She's trying to use my kids as an excuse as to why I can't move away but she doesn't even try to visit them. She used to have her grandkids every weekend to spend time with them and now she's saying "she has a life" and I told her okay well that's not my problem and I'm not staying where I don't want to stay because you MIGHT visit them. She used to be a very involved grandmother and now she couldn't care less and she wants me to stay for that? If anything it's motivation to move even more. When my kids get older and don't want to make an effort to get to know her she has no one to blame but herself. She's constantly promising my kids she'll pick them up and have lunch with them and they're empty promises and I'm tired of her doing that to them. It's so disappointing because this is the only grandparent my kids have.