If you stay for more than 5 years, that qualifies you as a taxing resident. Meaning you can file tax return as a US citizen using 1040 form. But that doesn't mean you will get a green card after you stayed for more than 5 years. This is what they get confused. A resident alien means you are a green card holder. If one stays for more than 5 years and get green card automatically, I believe lots of people here will not suffer and no longer need a lawyer.