You invented a fictional group of people, got mad at them, then declared what you imagined they did was wrong.
I want you to know that.
Musk came into Tesla as funding. People were trying to make the cars.
With regards to SpaceX, he was looking for people to build rockets to go to Mars. But no one wanted to sell to him. So he hired rocket scientists to build the rockets.
And yes, while there will always be some asshole who says "That won't work", there were plenty of ""real experts"" who were working at those companies.
And the "real experts" left us dependent on Russia for launching a couple capsules a year to the space station.
They could have done what Musk did with Falcon 9 in the 90's. Instead they chose to mess around more with solid fueled heavy lift vehicles, all the while proclaiming that they were the experts/science.