I'd be surprised if most people at microsoft paid more than $100 a year in health expenses.
Premiums are about $12K for singles and $25K for families.
As a “high” (by UK standards not US ones) income earner in the UK the “cost” of your health insurance/benefits would be considerably higher than the cost in the US but the benefits won’t be dependent on your continued employment.
The reality is that the compensation in the UK/EU is overall rather pitiful especially when you account for the higher taxation and the employment costs to the employer are much higher which is one of the main reasons for the lower salaries rather than the employers don’t need to cover benefits.
For a taxable salary of £115K which is on the higher end of what you can get in the U.K. these days the employer NIC is £13,885 that’s 10% contribution on top of the salary alone the employee is then pays over £6000 in contributions also.
The part often left out of the discussion of how much better government benefits are in UK/Europe, is how much higher salaries are in the US.