It's not always true.
Waymo is a clear exception: their car was at current Tesla's level 5 years ago, but they chose not to run into production. Many Google engineers left from the team because they wanted to see their work in public, but Larry clearly wanted safe L4 driving before getting to the roads.
(of course Google did lots of ,,ungoogly'' things in the past few years, but at least they got Waymo right)
That is something that "tech" companies will in all likelihood never be able to do, since they seem uniquely designed to betray and lose the public's trust at the earliest opportunity.
"Tech" companies have become far too culturally accustomed to dishonest hype, "growth hacking", marketing BS, PR spin, etc. for their statements to be trusted, especially when there are life-and-death implications.