More likely that Google decided that Usenet has declined enough that
there's inadequate benefit for them to continue.
I think that part of it may be in how much of a conduit that Google is
for spam in newsgroups and where they can't do much (at least at
reasonable cost to them) to stop it. I've seen mail-focused newsgroups
that have had a lot of discussion about how users can filter the volume
of spam originating from Google.
Usenet isn't going away, just that Google is declining to participate.
Thus, to keep access to newsgroups, Google users will need to find
another Usenet provider. Some are paid, some free. I've been using
eternal-september.org for a couple of years. It's free, and works well
for me. You do have to set up a user ID to connect, but that's easy
enough. And you'll need to find a news reading client. There are
several dedicated news clients out there, although the news capacity
built into Mozilla Thunderbird may be sufficient for many.
Smith