It's clear age verification is coming from a changing legal environment around the world. Discord may be preemptively moving, but any competitor service is eventually going to have to age verify users before they access adult content.
Maybe but I just don't see this as a certain thing. The US may implement nation-wide age verification laws someday but it is a long ways from happening. Other discord-like software may be self-hosted by individuals, making enforcing age-verification difficult. There's nothing wrong with this. People would rather have a private place to chat as opposed to a place where your data will be observed by a big company and potentially sold or given to a hostile goverment.