Spectre is a new class of attack, different angles on how to explore it to attack the CPU will be discovered, Spectre will not go away easily.
One of the NG flaws is said to significantly improve previous exploitation methods allowing for very practical attacks.
Security vulnerabilities are like that. One finds a security hole and is able to pass only a small needle through it. People say, well, just a tiny hole, not too serious, no one can steal much with a hole the size of a needle. Then, someone finds a way to pass an entire 747 jumbo through that same hole...