Having followed SpaceX since the beginning, this is not true at all. People doubted every single step. Industry experts did.
People doubted the claims, too. Particularly landing and re-use.
Concrete example: https://spaceflightnow.com/2015/04/13/ula-plans-to-introduce...
This doesn't really sound like doubting any claim; he's talking about how his organization was approaching it given their limited resources.
The DC-X was program developed in the early 1990s expressly to prove the feasibility of orbital rocket vertical landings and rapid turn-around/reuse. It never made it to the full orbital regime because it was scrapped early, but it was considered successful in proving the proof-of-concept. It was also managed by the predecessors of ULA (McDonnel Douglas, which later merged with Boeing).
Tory Bruno saying "no one has come anywhere near close to demonstrating these economic sustainability goals".
https://www.teslarati.com/spacex-critic-ula-ceo-reusable-roc...
> “We have not really changed our assessment over the last couple of years because we have yet to see the other forms of reusability—flyback or propulsive return to Earth—demonstrate economic sustainability on a recurring basis. It’s pretty darn hard to make that actually save money… We’ve seen nothing yet that changes our analysis on that,” the ULA CEO said.
> The ULA CEO’s points about the possible lack of savings on reusable rockets put him in stark contrast with other noteworthy leaders in the space industry. Apart from SpaceX CEO Elon Musk, fellow billionaire Jeff Bezos of Blue Origin is also intently focused on using reusable rockets. Even Rocket Lab CEO Peter Beck, whose company designs and launches small rockets, has embraced the idea of reusing previously-flown boosters.
The technological viability was shown with the proof of concept. If you meant strictly economic viability was unknown, I agree with you. This isn't meant to disparage SpaceX. They're doing great. I would say there is a risk that isn't often talked about which is the quality risk. Early on, SpaceX disregarded well-known quality control checks, presumably because they didn't think they were worth the time/cost. When that burned them, they integrated those checks. Do that enough times, the economic viability erodes.
They're close enough, functionally.
That's JWST-style stuff, not SpaceX at this point.
40 years ago it was questionable whether it was technically possible. It was “JWST-stuff”. The forerunners of ULA showed it was feasible.
20 years ago it was questionable whether it was economically viable. SpaceX changed that.
Your previous statement was too vague to make the distinction and implied Spacex did both, while ignoring the contributions of the previous group.
Again, what do you mean by “it”? Economic viability? I already stated I agree with that. Technologically viable? I disagree, since the proof of concept was shown decades earlier. We don’t need to to keep going around and around this point.