The "long engine list" is only 3 deep, none of which besides the raptor made it past the test stand. What matters is full-flow-ness, not staged-ness, which mea

The "long engine list" is only 3 deep, none of which besides the raptor made it past the test stand. What matters is full-flow-ness, not staged-ness, which means running neither oxidizer- or fuel- rich, for maximum efficiency. And in any case the russian engine was N2O2/UDMH and the american prior art was hydralox, so it's not like spacex didn't have to do a TON of figuring out to get a methalox FF engine up and running.