I don't understand what point op is trying to make with this. What does Facebook or Telegram has to do with Bitcoin
Your Ampleforth "stablecoin" is an interesting idea. I just went through it online. It is not really a stablecoin though.
Well, Facebook and Telegram was working on their own cryptocurrency or their own variety of digital coins if you would read the article that OP provided you would surely know the relations with facebook and telegram regarding the bitcoin and the technology behind it,
And for the Stablecoin, you are talking about they are like cryptocurrency but was powered by fiat currency so they would render their price with the market of fiat currency that is why they are called stable coin, And linking it to the project of facebook and telegram even though they said that it is most likely would run on blockchain I would doubt it will work, But in my opinion there is a big chance that Facebook may succeed than telegram, I can say that Facebook has a lot of users than telegram and people that are using Facebook will surely got hook in using its digital coin, But let see if they can really pull out a stunt as bitcoin did,
And by the way, Bitcoin is not a failure for bitcoin enthusiasts like me it sure needs time to recover but it will not become end up in zero and will continue.