I worked at a startup 25 years ago, and we had trouble getting group health insurance for our company of just over a dozen people because the accountant was over 50 years old, and it's not like we were going to fire him to get insurance. I imagine the problem is different today with ACA.
The costs are higher today than 25 years ago. A dozen employees at $150/month/employee (10% increase at $1500/month) is nearly $50k/year. That's meaningful money in a lot of contexts.
It's also worth considering that most older job candidates aren't in a highly skilled occupation like accounting where experience often adds value. Most employees are more fungible, particularly outside the world of startups.
Just for clarity HIPAA changed the landscape for pre-existing conditions in 1997.
