Definitely not. Stable coins don't really affect the market imo. They are semicryptocurrencies that are completely controlled and thus have nothing to do with the stuff that happens with decentralized coins. I like it that the article is staying realistic about stable coins by mentioning some of the failed projects as well as doubts about tether. I hope that Facebook will indeed back up their coin and guarantee long-term stability. This could actually make their coin the most popular, because it's the most famous company that is launching such a crypto. It might also be a positive thing, because it will familiarize a lot of people with what blockchain is and how it works. Perhaps, after playing around with facebook coin, they will turn to the main crypto market.