"Execution is everything" is not tautological. It's not saying "execution is necessary" — it's saying that how you execute makes an order of magnitude greater difference than what idea you pick. Good execution will save all but the worst ideas, but an amazing idea will still fail if not executed well.
For example, Apple's Newton PDA: Great idea — it caught on like wildfire when Palm did the same thing a few years later. But it flopped when Apple did it, because Apple's execution was flawed.
For example, Apple's Newton PDA: Great idea — it caught on like wildfire when Palm did the same thing a few years later. But it flopped when Apple did it, because Apple's execution was flawed.