According to boring company: Many of the speed improvements come from the design of the system. Smaller tunnels, automatic stone placement, removal of dirt.
Building rockets wasn’t new, landing rockets wasn’t new, grid fins weren’t new. But now we have an 80% reusable orbital launch system and he’s working hard on the other 20%.
Likewise with the Boring Company. Of course they still need to prove themselves, but the factors that work in their favour in tunnel construction are the same ones that favoured SpaceX.
ULA and the established rocket manufacturers made big profits off the fact that launching rockets is stupidly expensive. That meant their profit margins ended up being stupidly large quantities of money. Musk’s contention on big tunnelling projects is that big construction companies have similar incentives not to reduce the costs of tunnelling. However Musk as an outsider is free to innovate and develop the engineering and technology because he doesn’t have big fat profits he’s already tied to.
Others weren't doing the same, because they very specifically claimed that doing it at all was flat out technically impossible, so they didn't even consider looking at the economics.
Landing and reusing the first stage booster. This is why Vulcan is designed to only recover the engines, because recovering the whole booster while still launching a useful payload was thought to be impossible. It was thought that the stresses of re-entry would be too severe without excessive weight increases and that it would not be possible to retain enough fuel for a propulsive landing.
These things have existed for a century now. The fact that no one tried and it took a person with money from early dot com start up exit means others goofed up enormously.
Anybody could have tried. They didn't. Pulling down other peoples achievements because one didn't try the obvious themselves already reeks of envy.