Airborne was always known; debate was droplet vs aerosol (particle size and thus dwell time/radius). Not really a binary distinction anyway; a matter of degree.
I agree it's not binary -- and the SARS CoV2 debate, in particular, became a theater of the absurd -- but the categorical distinction is not entirely crazy: some viruses are much more sensitive to drying out or exposure to the environment and simply cannot transmit efficiently in tiny aerosols.
Tons of work has gone into weaponizing smallpox, for example. It's a non-trivial thing, even though smallpox is technically already a virus that transmits via aerosol. Many viruses will exist in saliva, and will happily transmit through direct contact, but won't transmit well via the air (mononucleosis comes to mind).
A fair large degree though. However, as I understand it, it wasn't a misconception unique this particular coronavirus. But that the entire medical field just had a longstanding, bad understanding of dynamics. So its not like the Wuhan lab was sitting on some crucial information, they almost certainly had the same misunderstanding.
I think it’s a textbook example of poor science communication. The words of science do not mean to the public what they mean to scientists. Further, it’s safest to assume the worst in a situation like that. I think they should have erred on the side of “assume it’s airborne.”
Unfortunately, special interests (hospitals and other medical groups) had an incentive (security of their own access to masks) to mis-state the facts.
