But does that mean it's a better way to do things?
I'm very much unconvinced so-called efficiency is necessarily the best policy. The nature of what's considered good needs to be qualified - good for what and whom?
You are spot on that Space-X's methods have garnered impressive results, but are those results a net gain for humans, or a net gain for only some humans, and at what cost to the rest? (rhetorical but relevant question imho).
When you consider efficiency, you need to start to consider what is waste and from who's perspective. Efficiency for one group may very well be negative for another (actually I doubt it's ever anything but).
Given human nature, especially based on what I perceive as our current trajectory, I'd say these phenomenally rapid developments are not for the best, especially considering their drivers which generally have little to do with our growing into something better, or have anything but an ever worsening environment.
We seem to be a complex chemical reaction that's occurring ever faster and in doing becomes ever more unstable and reactive - we're burning ourselves out rapidly because we don't consider our actions and control ourselves rationally.
If your goal is to innovate quickly, you must test "the model" intensely, and that means pushing the limits of the design to failure, adjust, and retest the limits. Within the context of a corporation that is putting out a product and are on a rapid trajectory and timeline, then there really isn't any other way. You must have your engineering teams putting their heads together and give them the autonomy to do what they've been trained to do without administration and accountants micromanaging every little thing. Tesla engineers do not design by committee, but rather at the speed of thought. It's a very rewarding job experience.
Is SpaceX's efforts a net gain for humans? I am inclined to think so. (1) We NEED to be a space-faring society if our species is to have any chance to live beyond a cataclysmic event on Earth (2) There are raw materials out in space that we could use instead of mining on Earth (3) If we are to have a broader perspective of our place in this universe, we need to explore and perhaps meet other cultures (4) Communication on Earth is still a bit "spotty" and there are areas that need to have internet access, that don't, that are trying to advance. Even in the US, there are many, many areas that do not have cell phone coverage or satellite communication. So, I suspect that other countries are likely in the same situation or worse.
Now, SpaceX is a private company, so what they do is up to them, for the most part. They are running a business but also have connections with the US government in terms of communication and military contracts. It is privately funded by private investors, not publicly traded. To suggest that Elon Musk and his investors would better serve the people of Earth by donating their money towards efforts closer to home is probably a false narrative. Any time money is donated, a good chunk of it gets consumed by the bureaucracy, and a small amount to the people who actually benefit from it.
We are probably better off with our efforts to eliminate fraud, waste, and abuse within our own governments and opening up money to then be routed towards people in need, dropping taxes, dropping inflation, etc.