There's an eye for history as you put it, and then there's misty-eyed nostalgia for a period of utter political impotence and widespread failure as a political party. The fact that people like Mason can even express a sentiment like that surely tells you they're more interested in ideologically-pure opposition than in gaining power and doing things.
And that's the real problem with seeing 2017 as a victory, of course. It sets a limit on your ambitions and tells everyone you don't ever really expect to actually win.