I would like to know the meaning of "would" in the next sentence.
These days, you would never see a concert billboard in the U.S. with a cigarette logo on it.
The sentence is true and correct without "would".
"Would" makes it conditional. What is the condition? -
"Even if you could drive down every highway ...
"Even if you really tried ...
"If you ever went to America ...
Sometimes, a sentence is expressed this way to overcome potential objections.
A: "You never see billboard cigarette ads in U.S. any more."
B: "True, but I rarely leave the house / True, but I don't live in America
A: Of course. But I mean 'You never would see them, even if you went out ... / (add the negation of the objection here).