I have no doubt that obama-care has a lot to do with it. The cost to cover health insurance for a young person is a small fraction of covering someone in their fifties and sixties. It amounts to thousands of dollars per year difference.
That certainly was the case with my clients. They did everything possible to keep their FTE headcount below the minimum required for participation in ACA-compliant health care plans ("Obamacare").
A corporation where I was once employed laid off everyone who was within six-months of vesting in their 401K company contributions. No provable age discrimination as this simply churned the staff in all age groups.
"It wasn't worth going to prison over".
If you think this started with Obamacare then you're naive. This has been going on for years and years.