Actually nobody is too busy, it just means you're not their priority. I know it's hard to digest this, I've been on both sides of this situation. It's hard these days, generally people are getting colder and colder and preoccupied with their own interests, they just say they are busy and proceed to ghost you. I admit, I also did this with some toxic people but that's life, sometimes you have to choose yourself.
You see people online on social media giving likes on posts but they ignore your text message for hours. It just means you're not important anymore in their eyes. It's sad but it's true, it happened to me on the basis that they hate what I do because deep down they also want to do it but they can't. People are reacting quite naturally to prioritizing the things they like and want to do the same with the people they want to be with. So while they may be ignoring your texts, they are also busy.