Should PS plus titles become permanent buys if you get the DLC for them?

[brute]

What are your thoughts on this? As most of you are aware you lose access to the "free" PS Plus titles once your subscription runs out.

My question is, should they become permanent in your library if you invest in DLC for them? At the very least their season pass? 

I know this can get tricky but I feel if we buy an extension of the game for a certain amount it would be nice to permanently only the game as well.