It's just another way of saying "Ideas are worthless, execution is what matters" which has always been largely true.

Yes, you need the idea first of course. But that's truly the easy part. 99% of "ideas" rely on great execution to be worth even looking at - much less paying for - for anyone else.

That isn't what it's saying and I don't think the idea that "execution is what matters" is even true, other than to point out that ideas aren't valuable by themselves.

This is about marketing, about getting people to know and care that the thing you built exists. You can execute perfectly (in terms of making a great product) and not get a single eyeball.