You are vastly underestimating the value of 3h (Bay Area average) of out of each week if one commutes 5 days a week. 3h*50wk = 150h - assuming $100 (lowball) bill rate that's $15k. A more median bill rate would likely be about $250 meaning it's probably worth $50k.
> Well then you could consider remote jobs to be worth £2k+ more salary, net.