When most people say "50% of their income" they tend to mean on a marginal basis.
Now that Donny capped state, local and property tax deductions at $10,000 per year (meaning you get double-taxed on the rest) and reduced the mortgage interest tax deduction cap from $1M to $750K, that number got much closer.
At $300,000 you're paying 48.65% marginal. That doesn't include, in SF, a 9% sales tax, a 1.188% property tax (that of course even renters pay as owners use rental income to offset that cost), and to your point, luxury and gas taxes.
Now that Donny capped state, local and property tax deductions at $10,000 per year (meaning you get double-taxed on the rest) and reduced the mortgage interest tax deduction cap from $1M to $750K, that number got much closer.
At $300,000 you're paying 48.65% marginal. That doesn't include, in SF, a 9% sales tax, a 1.188% property tax (that of course even renters pay as owners use rental income to offset that cost), and to your point, luxury and gas taxes.