Yes income from CA sources is taxed by CA even if you live elsewhere and earn most of your income from other sources.
No, if you do not go to CA to work there, you do not pay CA tax. You pay CA tax only if you work in CA.
Read about taxes for two states:
if your moving to las vegas is considered temporary or transitory then you must report your income to ca even if you live in nv.
however, if you permanently move out and have no intention of going back to ca then even if you employer is located in ca you do not report income to ca. this is a common situation. many people have employers who are out of state.
just a note. if you employer happens to continue to deduct ca income tax, then file a ca tax return with zero income so you get ALL the withheld funds back. also, include a note explaining that you are not a resident nor did you ever work in ca while you earned that income.
but if you left to nv at part year, then ca gets to tax your income that you earned while in ca and nv gets to tax ALL your income. but don’t worry too much about that. nv will give you a credit for tax paid to ca.