To get the J2EE compatibility mark for a J2EE spec implementation
you first need to be a licensee of J2EE
You can either spent the money needed for the JBoss Group to become a J2EE licensee or buy a new house with that money. Up to now people decided to buy houses instead.
Nevertheless JBoss is in sync with the J2EE specs and has an own testsuite to ensure that. That's why nearly half of all J2EE developpers decide to develop with JBoss.