What did he do that others considered unthinkable? This is not a rhetorical question. Please give me a concrete example, with sources proving experts in the field thought the idea was "unthinkable".

Robofactories? The idea was roundly mocked and completely failed, costing many millions of dollars, leading to manufacturing defects on thousands of vehicles, and delaying Model 3 mass production.

Hyperloops? The idea was roundly mocked and completely failed. Somehow it attracted hundreds of millions of dollars of investment. (There's suspicion Musk proposed the idea cynically to distract from rail.)

Robotaxis? Waymo started in 2004 and is, today, ahead of Tesla.

Electric cars? Again, demonstrated long before Musk got involved. The frustration amongst environmentalists at the time was that the technology and demand both existed but manufacturers weren't interested in making them.

https://en.wikipedia.org/wiki/General_Motors_EV1

(Before you claim the EV1 was so obscure as to not count, GM built about 1,000 of them, vs 2500 Roadsters. If it doesn't count, neither does the Roadster.)

Reusable launch vehicles? Work started on them in the '70s at the latest and they were the American workhorse by the '80s. The basic design SpaceX settled on was demonstrated in the '90s.

https://en.wikipedia.org/wiki/Space_Shuttle

https://en.wikipedia.org/wiki/McDonnell_Douglas_DC-X

Satellite internet? Obviously old hat, so let's restrict ourselves to LEO constellations. These were proposed in the Star Wars project and were built by several companies in the 1990s. Starlink is much larger and more modern, but the basic idea was proven.

https://en.wikipedia.org/wiki/Teledesic

https://en.wikipedia.org/wiki/Iridium_Communications

https://en.wikipedia.org/wiki/Globalstar

This narrative that Musk has done things other people considered impossible is simply untrue. Everywhere he's found success, other people had already demonstrated the basic idea. Everywhere the consensus was that he had lost the plot, he failed completely. Impressive work should not require exaggeration.

I will have to grant that this was previously unthinkable:

https://tinyurl.com/5aps6aam

Google’s Project Suncatcher to put ML infrastructure in space