That's basically been the conventional thinking about rocketry historically - scientists and engineers looked at the tyranny of the rocket equation and choose to maximize payload per launch because they were largely funded by government or quasi government "cost plus" types of contracts. The design philosophy of working close to margins comes from this thinking.
SpaceX's greatest contribution has been to look at rocketry from the point of view of economics of running a rocket launching business as opposed to a "per launch cost plus" model realizing that fuel cost for launching a rocket is close to trivial compared to the facrication cost of making a rocket.
So their entire design philosophy is around reusability and reusability seems to push costs down low enough that you can get more payload up by simply doing more launches. While SpaceX is famous for not filing patents and instead protecting their IP using the trade secret approach and fabricating everything in-house, you can bet they'll be operating with more engineering headroom to get reliability and reusability.
Evidence for their bet having been right is the fact that they have grabbed virtually 100% of commercial and quasi-governmental launches and some part of US government launches. Other players in this space now almost entirely depend on defence contracts or national prestige contracts to survive.
Doesn't matter. If you take the conservative assumptions that go into manufacturing, say, a car and apply those to a rocket, you'll get something that won't even lift off the ground, much less make orbit.
Any rocket HAS to be very close to the limits of what materials used allow, and not the +50% margin of error you routinely seen in other fields. What you say about SpaceX is true, but only relative to the rocket industry as a whole. E.g. SpaceX uses cheap, available materials and simple designs over exotic composites and complex mechanisms. But they still operate close to the margins, as they have to in order to have any payload capacity at all. In fact, the move to steel probably reduced their mass margins even further.
SpaceX's greatest contribution has been to look at rocketry from the point of view of economics of running a rocket launching business as opposed to a "per launch cost plus" model realizing that fuel cost for launching a rocket is close to trivial compared to the facrication cost of making a rocket.
So their entire design philosophy is around reusability and reusability seems to push costs down low enough that you can get more payload up by simply doing more launches. While SpaceX is famous for not filing patents and instead protecting their IP using the trade secret approach and fabricating everything in-house, you can bet they'll be operating with more engineering headroom to get reliability and reusability.
Evidence for their bet having been right is the fact that they have grabbed virtually 100% of commercial and quasi-governmental launches and some part of US government launches. Other players in this space now almost entirely depend on defence contracts or national prestige contracts to survive.