Everything you have said is true, everyone is here for at least one of the reasons listed. Even those who were introduced to the forum as a means to earn from bounties later changed their perspective and became interested in Bitcoin.
6. Business ideas.
From this forum you can get a lot of business ideas, there are a lot of discussions in the Bitcointalk forum and business discussions are not excluded.
If there's something I didn't add or I didn't explain well or if I'm wrong in any way, please I'm open for correction.
I’m not so sure about the business ideas part, it could be because I don’t frequent the Economy board as much. But I think such discussions would be common in local boards, the forum is mixed with people from different countries so businesses that are successful in x country may not be as successful in another country.