> The core problem that LinkedIn solves has nothing to do with all the "social media" style content that plagues the platform.
I feel like a broken record explaining this to people.
The feed that appears when you go to LinkedIn.com is a sideshow. Almost nobody posts to it. Very few people read it. You can (and should!) ignore it and not miss out on anything.
Make a profile. Update it occasionally when you're job searching. Forget about the site until you need it. Hit the unsubscribe button when they e-mail you suggestions.
The exception is people who simply cannot resist getting pulled into a feed and scrolling it. If that's you, I understand why you'd stay off of the website. For everyone else, it's a set it and forget it until you need it kind of website.
That's also why a second website isn't appealing to anyone. They've already gotten past the set-and-forget part. Why would they want to set up a second profile somewhere in a smaller, less useful network? There would have to be some real benefit, not an imagined talking point that disappoints.