Google Plus has been kind of dead for the last couple of years. In fact, it never really took off like other brands such as Facebook, Instagram, and Tumblr. It would definitely make sense if it became a spammer's hub, and it's very likely that it'll be a ghost town like MySpace in a couple of years.
As for your second question - if you're afraid of losing followers of your site, you can build a site on Wordpress or Wix, then tell your followers to move there. Or move to social media platforms like Tumblr and Instagram, with large user bases to grab a larger audience. If you don't, there's a large chance that you'll lose those followers, so be sure to tell them where to go so they can follow you elsewhere!