Jeff Findley writes:

Even LOX/kerosene engines were still "more expensive" when SpaceX
started up, which is why they developed their own engines instead of
buying them "off the shelf". But I see not fundamental reason why a
start up like SpaceX couldn't have built and flown a Falcon 9 in the
70's. But it would have taken someone like Musk to do it. Someone with
deep enough pockets and the vision to take on NASA head to head.

Well, friction-stir welding was invented in 1991. Al-Li alloys weren't
available in the 70's. Then there's a lot of automated manufacturing,
rapid prototyping etc. that was not at all available in the 70's. While
I agree that there are very few totally new things, there are lots of
small new things that helped here. A lot.


And I somehow doubt that modern computers, software, communication etc.
didn't play a role in keeping SpaceX small and fast. You could have done
this with what was common in the 70s, but you'd need more people, more
money, more time, more room, more stuff being handed and sent around...


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery