Answer: Unless you have resources, you're forced to work until you drop. The 'work above all else' culture is cheaper. Tying health insurance to employment guarantees you will work until you're eligible for Medicare. God forbid you lose your job in your 50s. You're too old to hire but too young to retire, so you're left scrambling to find a job AND crappy insurance on the open marketplace.
Why is US Health Insurance Tied to Employment - Vox