doggybag 1983 the Alliance polled 25.4%, Labour polled 27.1%. Seats 23 v 209. Looks like the electorate were brave enough to me and they managed to attract the voters who wanted a successful Liberal party. There just wasn't enough of them to "Break The Mould". They also got the arithmetic badly wrong.
It's interesting that your scorn is for the voters who identified more with Michael Foot's Labour Party rather than people who voted for the Conservatives. Williams lost her Crosby seat because the Tories took votes off her (though there had been gerrymandering of the constituency boundary).
In truth both were probably fucked over to some degree by Maggie's masterful milking of the Falklands War. A warb which was a staggering (to me) display of patriotic hysteria that pre-dated the Princess Di weepathon by about 15 years.
However back to the Gof4, Labour enough to stand for election in 79, less than two years later not Labour enough to fight for the soul of their party and to aid and hasten the leftward shift, which probably peaked in 84/5.