Becoming a professor is called getting your 'chair' isn't it? I don't know any professors who don't also have tenure - that seems a contradiction in terms to me.
But if you don't know what I mean we're probably talking about different things and possibly talking at cross-purposes.
Yes, it is true that there are SOME professors with chairs. Not that all professors have a chair. analog31 already explained this in response to your last comment.
The professors I’ve worked with usually only get that title when they have a couple of decades of experience and are at the very top of their fields with international recognition and will of course be funded and tenured. It sounds like you’re using ‘professor’ to mean something far more junior which is why we aren’t understanding each other.
The terminology gets even stranger. ;-) A "chair" is a professorship that is funded by an endowment, that gets naming rights. So for instance, you might see someone like: "Bob Smith, Alice Q Hammond professor of situational metaphysics." What it means is that Alice Q Hammond gave a bunch of money to endow a "chaired" professorship, that Bob Smith occupies.
There are "chairs" like this in professional orchestras too.
The taxonomy of academic titles could fill a book.
An "endowed chair" is the best type of full professorship, but it's an exception rather than the norm. There are elite institutions where most full professorships are endowed chairs, there are very wealthy institutions where that happens for lower titles, but in general most professorships are not as such.
Furthermore, it's not something that's available right away (exceptions do happen for exceptional people, but they're exceptions).
For a random example of a successful professor, look at the carreer ot Terrence Tao (https://www.math.ucla.edu/~tao/preprints/cv.html), James and Carol Collins chair in mathematics at UCLA. He got his PhD in 1996, got full professorship at 2000, and was a non-tenured non-chaired Assistant Professor for the four years in between.
Seriously, just look up a random professor from your local community college (not something like Stanford) and take a look at their CV - how many years it took for them until the full professor position.
Becoming a professor is called getting your 'chair' isn't it? I don't know any professors who don't also have tenure - that seems a contradiction in terms to me.
But if you don't know what I mean we're probably talking about different things and possibly talking at cross-purposes.