That depends on the details. I'm sure to have missed a many important details below (I doubt anyone even knows them all).
For an instant raise to happen: companies must not only lose their tax deductions on what they contribute to insurance, they also need to count that contribution to employee's wages even if the employee doesn't take it. As soon as young childless employees realize that they are paying taxes on what amounts to the insurance payments to their co-worker who has a lot of kids they will demand they get the cash.
For an instant raise to happen: companies must not only lose their tax deductions on what they contribute to insurance, they also need to count that contribution to employee's wages even if the employee doesn't take it. As soon as young childless employees realize that they are paying taxes on what amounts to the insurance payments to their co-worker who has a lot of kids they will demand they get the cash.