Yes, because that beard makes him look like a whole other person...I know when I grew my beard my wife didn't recognize me anymore.The long hair didn't conveniently obscure his face.
Seriously. I get your point of view that Spock is Nimoy. I don't share it, and it would be supremely limiting for actors to pretty much be told that you can never revisit a character because only one actor owns it. That defeats the whole purpose of acting and franchises.