How come Hogan and DiBiase never had a truly direct feud?

Scott,

While Hogan and DiBiase feuded for years, through proxies, how come they never had a true, direct feud where there was a singles blow off at a WM or even Summerslam? They always seemed to have hot chemistry and even worked well in the ring. What gives?

Just timing. The original direction for Summerslam 88 and/or Wrestlemania V was Hogan v Dibiase, but then the tournament got all changed around by circumstances and the Savage thing fell into their laps instead.