With regards to "But what if you have bad knees or live in a dangerous neighborhood or simply don't like walking?"

This is very simple to fix: thing about this in terms of equity not equality. Do not eliminate a benefit but think how can include more people by changing the metric.

If someone has bad knees or don't like walking but still want to participate in this subsidy then the fix is not to eliminate the subsidy for everyone, but to have different metrics for people to opt in.

Then your health insurance billings will likely be higher, and you’ll be more expensive to insure, which pushes up the company group rate. Measures like getting employees to exercise more fall under the umbrella of “preventative care”

Really? How does this work? Your company tracks how many steps you take?

Don't walk 7000 steps and don't get $750?