How would you craft legislation that force Google and Facebook to do business with you under terms that you dictate? Ultimately how can you prevent said companies from pulling out of your country entirely if that's the better option for them?
Australia and Facebook did exactly what you described in your "impossible" hypothetical. I suspect the government's thinking was the Australia is too big a market for the victim companies to drop, i.e. they thought this was a deal they could not refuse.
No they didn't. Google isn't being forced to operate there; there's simply an additional cost of doing business being imposed. Clearly it's not in excess of income from Australia if they're continuing to choose to do business in the country.
I couldn't; I believe I originally thought you were suggesting these companies can't be expected to exert political will/make consequential decisions for some bizarre reason