Lifetime Powertrain warranty... Is it really good for life?

I recently contacted the dealer to schedule an appointment for a leaking valve cover gasket. I asked to confirm this was covered under the lifetime powertrain warranty which they said it was but the warranty was not a lifetime warranty and expired in 2011, which was only 3 years after I purchased the car brand new. They then informed me that because I failed to take the car in after 5 years for the powertrain inspection that the warranty was voided however I was never notified by paper or verbally that this had to be done The warranty is confusing, what do you guys think?