Out of 3.000+ B-29s, 119 were destroyed in the US in accidents.
87 in accidents in theater.
105 sent to 2nd line due accidents, malfunctions and damage.
That is not very far from the 414 actually lost in combat.
Btw, picking a single He-177 early mission as indicative of the performance and reliability of a later model of the aircraft is highly misleading! And also ignores the fact that in the eastern front the plane did quite well, that is until it was sent in suicide, low-level, anti-tank runs.
For what I have read, people seem to be concerned about other aircraft losing its place to a new one... but how many times has this happened in AH before and why should we care?
Oh, and regarding its strength, this crate was designed to and did withstand shallow dives so it structure was quite strong, the engines however should catch fire easily and take away half its power and eventually causing a wing collapse. Just like happened in the B-29.
The Ju-188 is a beauty, sadly it offer little improvement over the Ju-88A4. Its slightly faster and has better guns, but that is pretty much it. The plane was a stop-gap measure until the stillborn Ju-288 could enter service. The He-177 in the other hand brings a whole different dimension capability-wise, its reasonably fast, it has a bomb load second only to the Lancaster and its armament is good, but not as good as that of the US heavies (the 20mm tail gun has very limited firing arcs and the 13mm is not as good as the .50, and lacks a belly turret).