Frankly, it kind of blows my mind what the US pulled off in the late 60's, early 70's with the technology and materials of the time.
That said, I hadn't fully appreciated the size of Saturn V either until I saw it in person in the museum. Like, I had felt it was big, but it was big.
It's way harder to do it the first time.
Manufacturing the Apollo Guidance Computer (which wasn't in the rocket per-se, but was wired up to it and could fly the rocket in certain scenarios) alone consumed around 40% of the US' entire IC production capacity at the time.
raptor engines are designed to be cost efficient, as is the rolled steel? that is used for the fuselage
As with any manufactured item, high volume and iterative design improves the production process and finished product.
Also, SpaceX is not building rockets, they are building a rocket factory. If they succeed they will have lowered the cost of putting stuff into space by an order of magnitude. The potential rewards are huge.
Starship has considerably fewer moving parts. And googling 'evolution of raptor engines' gives you some pretty stark images on how simpler things look, in principle.