Don't forget health insurance! Larger companies have larger risk pools and can afford better health insurance with lower premiums and co-pays for employees than small startups can. Especially as workers get older (and that experience becomes more valuable for startups), the value of healthcare can become a surprisingly large percentage of compensation.

Source: I have family close to retirement age that had significant health issues in the past year, and they estimated that their insurance paid probably $200,000 in the last year alone. Works for a BigCo, not in Silicon Valley.