We only have a few remaining copper lines (landlines) at my job, and are working to replace those with VoIP lines before the end of the summer. If we do it by then, we won't have to renew the contract for those few (almost unused) lines.
At home, I can't remember when I last had a copper phone line. In the 2000s the cable company offered phone service packaged with their cable TV and internet, so we started using that instead of copper. I last had such a phone line in 2015 or 2016. It just wasn't worth the cost, since I used my cell phone for any calls (not because I'm a technophile, but because I hardly ever use the phone!). Honestly, I'm wondering how many copper lines are still in use.