In California, you will be paying 30-40% in taxes (Federal, State, Social security etc) if you have a well paying tech job paying more than 250K USD. Even after those taxes, you will be taking home 60% of your pretax income, which is around 150K USD per year. After accounting for very high living costs (3/4K rent, 1/2K living expenses, insurance premiums), you can still have 20-30% of your pre-tax income.
Also, if you have heard crazy stories about American healthcare, rest assured that a tech job paying you 250K USD will also offer you very good insurance that you don't have to worry about it generally. I am an immigrant, did this exact calculation and am living a far better lifestyle than what I could ever afford in my home country.