What is taking Samsung so long to update to LP 5.1.1 ?

I heard that LP 5.1.1 is the most stable. We are stuck in 5.0.2 on Note 4. So is my Tab S. So is my Alpha phone. All at 5.0.2

Why is Samsung so slow? I think they might have abandoned us.

Samsung screw up on Note 5 and all the updates are slow.

Its a bad company.