It wouldn't have been any worse
Could have been a lot better. We'll never know.

Not sure where you get he idea Corbyn is economically illiterate from. Labour's manifesto was coherent and well costed. The people claiming it involved too much borrowing have now turned around and borrowed significantly more money, but instead of doing so to benefit the country they're doing so to corruptly enrich their mates.
( Cassius Kray floats like a butterfly, stings like a trout, Fri 18 Dec 2020, 10:16, archived)

Labour still lost the election heavily, though.
It was their job to convince enough people that their manifesto was sound. If they failed to do that, that was their failure, not everyone else's.
(The Porcupine From Purgatory we of all lost both have them, Fri 18 Dec 2020, 12:20, archived)