I'm sure it is. For the few people who use it. Once upon a time, it was the dominant versioning system out there. But it was supplanted by git. And it was supplanted for a reason. And network effects didn't protect it from being replaced by git.
What is your point exactly?
It's unfair to consider network effects when it comes to SVN because it was a very different time on the internet with no major centralized code hosting SaaS like GitHub.
Nowadays even companies (that would in the past self-host) rely on SaaS and are thus swayed by network effects of whatever is popular.