People have been saying this would happen for years
Ever since they bought Motorola their intentions were clear. I think they backed off out of fear at the time, because Samsung was making noise about building Tizen phones, and Android wasn't quite as established in the market as it is now.
I wonder if Samsung has kept a skunkworks project going for Tizen phones? I wouldn't be shocked to see that start coming up again, but they probably aren't big enough to go it alone. If they could get a few other big players to throw in with them on a new OS maybe they'd have a chance, but I suspect that infighting among the players would prevent such cooperation.
The Note 7 PR disaster couldn't come at a worse time for them, they really handed Google a perfect storm launch scenario when it would have otherwise been buried in the news beneath stories about the Note 7's success.