Most businesses aim for net income. Most startups don't even try, even if they've raised hundreds of millions of dollars and occupy fancy offices. (It's also very easy for IP-based businesses to shift where income is generated.)

And that's the basic reasoning behind SF's gross proceeds tax. It's a uniquely SV tax that only works because so many unicorns built their house of cards out of claiming revenue for things no other business would claim as revenue.

Yes, it would be great if we could have some kind of Generally Accepted Accounting Practices that would specify what counts as net income and what doesn't.

Why would you want to tax a startup that isn't making any money? The whole point of government taxation is to generate revenue from profitable business activity occurring there. Taxing businesses that aren't even making money is ridiculous.

And sure, you can shift where profits are generated. But you can also just not be in SF. Which is exactly what's happening.