Is there any particular reason you want to stop texting them? Some people are better at texting than others, and if they didn't want to talk to you at all they just wouldn't text back. I have some friends who would never, ever send the first text in a million years, but they are perfectly happy to chat to me if I text them first.
Heck, even my partner never texts me first, and I know I mean a lot to him.
You can't put so much emphasis on who texts first. Fair enough if you're texting people all day every day and nudging them if they don't reply you should chill out a bit, but if you just fancy a chat every now and again start one!