There’s so much modeling that couldn’t even be done 80 years ago. Electronic computers were in their infancy, climate science was just beginning, weather satellites (hell any artificial satellite) had not yet been launched.

The inputs, the models themselves, and the main way to compute an output had mostly not been invented.

This is a fundamentally unfair comparison. If it couldn’t be computed analytically, it wasn't really possible to compute it 80 years ago. That absolutely doesn’t mean we should just ignore these predictions. Are we supposed to always wait some arbitrary time before listening to long term prediction?