The ACA fundamentally shifted the landscape for the whole healthcare system with minimum coverage mandates (including employer plans), guaranteed issue, etc. It's also led to higher demand for medical services (ie because more people are covered - a good thing) at a time when the number of doctors has stayed fixed. The net result is that health coverage is simply more expensive. One way that could have played out would be employers eating the higher premiums themselves (which is essentially giving everyone a raise.) Anecdotally, it seems the way it's played out is that employers have kept paying roughly the same amount while employees have either paid higher premiums or received higher deductibles.