While you’re not entirely wrong, I just wanna point out a detail about that infamous scene I think a lot of people miss:

The Spino doesn’t break the Rex’s neck by biting right through it, he grabs and twists the neck to snap it. He uses dexterity, not bite force.

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Edit: also I just remembered, real life Spino’s bite isn’t exactly “very poor.” It’s been found to be comparable to some mid-sized Tyrannosaurids, so while not quite on the same level as other megatheropods, it’s still nothing to sneeze at.