The explanation is simple.
Glueball: "a rogue pilot's programmed low speed, low altitude flame out would result in a significantly reduced airframe breakup than a flamed out jet at cruise speed spiraling down from high altitude. This theory might explain the lack of debris found so far."
The "lack of debris" has a simple explanation, elaborate scenarios are not necessary. The aircraft went down in a remote part of a very large ocean. It was 10 days before they even shifted the search to the right ocean, and even then they had only a few search assets to cover an enormous swath of stormy ocean. The debris was there, but most of it sank before the search started, and the rest, including the flaperon was dispersed and displaced by wind and currents. As the search ramped up and the search area was refined, the sinking, dispersion, and displacement continued. Searching huge swaths of rough sea far from the nearest airport was a long shot, and when they did see floating debris they had no way to tell exactly what it was.
Compare that with AF447, where they found floating debris the next day, because they knew where it went down. If they had waited 10 days, and then started searching a huge swath of the South Atlantic it would have been a different story.