Russian government has no money to implement something like Chinese Great Firewall but feels an urgent need to censor online space so more likely scenario is a complete cut-off from an external world (like in North Korea). Russian ISPs has been tasked to prepare to operate all networks inside the country in isolated mode - like a huge LAN. Will it happen - no one knows for sure but there is a real possibility.

Even then, I can see a real market potential for bootleg sneakernet [1] dealers. VHS bootleg of western movies being dubbed by a single person were all the rage in the late 80’s Soviet countries [2]. If the internet is fully closed off, a new market for sneakernet of Internet segments would evidently emerge.

[1] https://en.wikipedia.org/wiki/Sneakernet

[2] https://jacobinmag.com/2017/07/soviet-voice-over-cold-war-te...

A major difference is that in China it's one-sided. Here we also have other countries cutting Russia off.

Even in China I think you can get around it or at least you could when I was last there although there was a little more hassle than in other countries. See https://www.vpnmentor.com/blog/best-free-vpns-china/ for example.