Nimoy has mentioned that he regretted that SHAT couldn't see past his own ego and connect with anyone else on the set. He was so absorbed in himself that he never noticed how much he was pissing everyone off. Nimoy escaped that fate by having a more popular character than SHAT and actually getting studio clout on his side. I guess you need to get SHAT to notice you first.
This coming from the guy who wasn't honest enough to admit that he was an alcoholic-for years!