You're missing the point, BitcoinNG is not going to be an altcoin. You missed this paragraph from the article: "It is worth noting that there is no conflict or

You're missing the point, BitcoinNG is not going to be an altcoin. You missed this paragraph from the article: "It is worth noting that there is no conflict or contradiction between NG and Blockstream’s sidechains; in fact, Blockstream’s pegs allow for moving bitcoins among chains, and such chains can benefit from improved performance using Bitcoin-NG. In future work, we plan to expand on how to incrementally deploy Bitcoin-NG on top of the current Bitcoin network."