They are little bitty compared to Saturn F-1s.
And the F1 engines never failed in flight. And all of the F1 engines that were ever used were dumped in the Atlantic, and were not as efficient as these Raptor engines are, by a long shot.
Up until perhaps fifteen years ago there was still an undercurrent of support to restart the F1 production. If there had been a plan for its use, annnnnnd there hadn’t been resistance to continued pork-barreling the US space program by a certain Senator, that might have come about.
OTOH, the SRBs on the Shuttle put out 2.5 million lb each, so three of those would more or less replace the Saturn V, and would be reusable (as reusable as the Shuttle components were in reality).
But as we’ve seen with the supposed SLS, just adding a section to the Shuttle’s SRBs, reusing parts (they’ve been flown before), and basically doing something that someone somewhere should remember how to do, they’ve come up short, and the SLS can’t get off the ground without them, any more than the Shuttle had been.
Oh, and the plan is, they won’t be recovered, regardless of how the whole thing goes in all other ways.
Meanwhile SpaceX did perhaps a bit too good a job with the Falcon 9, having made reusability a nice routine, having made engines that work right and are a tough act to follow, and having passed the 500 launches mark not long ago.
There’s some scuttlebutt about major improvements to the Falcon Heavy core booster design. In the past, those have been pretty poor in the recovery phase of flight.
https://en.wikipedia.org/wiki/Rocketdyne_F-1
https://www.nasaspaceflight.com/2025/08/b1091-heavy-core-falcon-9-clothing/
I’m not rocket surgeon, but I have to imagine redundancy is part of it.
A B52 has eight engines. Statistically, I supposed that a loss of an engine or two is greater there than on a two or four engine plane. The result of an engine loss on a B52 would be the so-called “dreaded seven engine approach.”