Meaning of verb + negative-verb

Question

While reading 君死にたもう流星群 vol. 4, I found this sentence:

黒井{くろい}の本はまったく売れない。いや、売れる売れないというレベルではなく、開始二時間が経つというのに誰ひとり客が来ない

Kuroi is attending together with the main character an event like Comiket, and she is selling her book, but no one is buying it; what does 売れる売れない mean? Initially I read it something like "It could sell, but despite this it didn't", but I'm not sure, since it doesn't really seem to connect well with the second part: in general it'd mean something like "It's not the it could sell but it didn't, not even a customer showed up", but no customer showing up doesn't exclude that the book could sell, so I'm not sure if it means that or something else.

Answer 1

• This 売れる is not a potential form of 売る, but an intransitive verb 売れる meaning "(for something) to sell well". Forget the potential れる.
• 売れる売れない is a noun phrase. In general, this pattern works with any verb and means "(a problem of) V or not V". For the grammar, see:
  • What does 似てる似てない mean?
  • VかV-negか vs. V | V-neg vs. Vかどうか
• レベル refers to the severity or degree of an issue.
• There is no such verb as 軽つ. It's 経つ.

いや、売れる売れないというレベルではなく、開始二時間が経つというのに誰ひとり客が来ない。

No, it's not even a matter of selling well or not selling well; even though it's been two hours since the start, not a single customer has come.