And of course it's ridiculous that engines like NK-33 are considered bad just because they sit in a hangar for some 40+ years :) . It's not milk, they aren't that easily spoiled. Elon just used this time reference to make the decision look good - for somebody who doesn't know better.
So factually he's right - but also misses the point. Here I should admit that Elon says more than he does - but he does quite a bit too, so kudos to his successes - Merlin-1D is a great engine.