SpaceX was able to accomplish it because they were actually trying. They quickly became the company to go to if you entered aerospace primarily to work yourself hard doing R&D, so they got all the best young aerospace engineers who just wanted to get things done rather than have their soul crushed by the bureacracy at the old space giants.
Meanwhile Boeing and the other old guard were full of jaded "it isn't that easy" types. It's difficult to innovate when your instinctual response to attempts at innovation is to look for excuses on how it won't be that straightforward, that it won't be economical, or that it won't make sense.
Eg, if we look at Falcon 9, first the arguments from old space companies were that launching to orbit is too difficult for an inexperienced company to do reliably ("they don't have spaceflight heritage"), then that they must be cutting corners to bring prices that low, then in the early days of F9 booster reuse, the argument shifted to saying that there wasn't enough stuff to launch to justify the expense (there was the ULA CEO's argument that, for them it'd take 10 flights per booster to break even or ArianeSpace's saying that they'd have to shut down the factories and lose expertise becuase they'd only need a handful of reusable boosters to fully meet demand).
Prior to the pandemic and the 737Max debacle, though, Boeing would low-bid fixed-price contracts and eat the losses because their commercial aircraft business would cover it, then make up the difference with continued sales. https://www.defenseone.com/business/2022/04/boeings-low-ball...
The only folks who weren't trying here were senior management, who were unable to do anything that wasn't milking the cost-plus contract cow.
Meanwhile Boeing and the other old guard were full of jaded "it isn't that easy" types. It's difficult to innovate when your instinctual response to attempts at innovation is to look for excuses on how it won't be that straightforward, that it won't be economical, or that it won't make sense.
Eg, if we look at Falcon 9, first the arguments from old space companies were that launching to orbit is too difficult for an inexperienced company to do reliably ("they don't have spaceflight heritage"), then that they must be cutting corners to bring prices that low, then in the early days of F9 booster reuse, the argument shifted to saying that there wasn't enough stuff to launch to justify the expense (there was the ULA CEO's argument that, for them it'd take 10 flights per booster to break even or ArianeSpace's saying that they'd have to shut down the factories and lose expertise becuase they'd only need a handful of reusable boosters to fully meet demand).
In a way, SpaceX's success is just an engineering version of Planck's principle (https://en.wikipedia.org//wiki/Planck%27s_principle?&useskin...)