Ability to pay all expenses, including things like sudden repairs, medical payments, job loss for up to 6 months, etc with minimal impact to quality of life.
Ability to partake in moderate luxuries such as travel, dining out, new phone/TV/etc every so often. Does not mean you have enough to always buy whatever you want, but have enough to have some extra enjoyment.
Ability to take care of 1-2 children including education, day care, medical, activities, etc
Just based on the healthcare component alone, I don’t think it’s feasible for Americans to be financially free until they hit the millions. Otherwise, if you ignore that aspect I’d say its around the mid level executive type of income or about ~$300-600k year depending on location. If it’s just moderate financial stability, then it’s maybe only $90-200k, but I don’t think I’d call that level ‘free’