Now, it's not because I know nothing about it. In fact, I know what kind of situation can build it up, and destroy it if you're over-zealous building it.
* When people keep saying that we should heavily build relationship...
Be careful! Over-doing it can backfire. The suspicious instinct is every human being.
* When people say that they don't need relationship...
Because they're getting sales without any marketing campaign. They think they're like the KFC or old Mac.
Again, be careful of such assumption. Relationship can be pre-built without you actually doing it. For example, your competitions are doing it, and it happens that the prospects also know competing product from you. They compare. And they make a decision to buy from you instead.
I think there's no fixed answer in this. What I can only say is, the better way is to build up the attraction and let potential buyers come to you. Never show your intention to sell. A man who wants nothing for himself is the most powerful being, so to speak.