So, now you are trying to change what I've said. You are not the writer. So, you don't get to decide whether the writer is referencing a time, or an alternate idea. But, you should be smart enough to know how to tell the difference when it's written as such.
Try to keep up;
Then is in regards to a specific time. First I brush my teeth, and then I depart home for work.
Than is in regards to an alternate idea. If I haven't brushed my teeth, than why did I depart home for work?
If the statement is not in regards to time, than the correct usage is than.
Not there yet? Here is another example.
Back then, we used to have wired headphones.
If we still prefer wired headphones, than why would we purchase wireless ones?
I see how it can be confusing. But you can actually have both words in one sentence to drive home the difference.
If we still prefer wired headphones, than why would we go to the store and then purchase wireless ones?
Than, describes the alternate idea. Then references the point in time that this occurs.