There’s a difference between not being good at texting back (most of mine) and not having any energy or interest in doing so (most of my ‘former’ or ‘mistaken’ friends).
The former is excusable and I have a lot of patience for it, the later I have zero tolerance for.
Not being good at it is for the socially awkward who never know what to say or when to say it or are afraid they’re bothering me. I will put in massive effort to stay in touch with them. But if I know you can text back and how do the kids put it? “Leave me on read” Then I have no time for you because I know you have none for me.