John Deere cut the retired insurance a year or so back, and have cut back on the current workers medical insurance.
Companies just can’t afford it. When those policies were put in place 30-50 years ago, people didn’t live as long, and end of life costs were much less. There are not enough workers, or profits, to keep paying 20 years of a non workers health insurance.
And that is what Medicare was designed to fix. Now it is universal health coverage for all paid by all. There are any number of reasons the new system is completely unsustainable.
For those firms that paid 100% of their employees health insurance, I agree with you. For those that require their employees pay say half of them, including retirees, I think that system works is in the out years, after 65, their current insurance becomes secondary to medicare. Otherwise, as you say, it is impossible for it to work given life expectancies.