In Russia between factory and front was not a short trip. Those tanks might have gotten painted while refueling, maintenance and whatever rest stops the crew had. Making the trip to the front becomes the break-in. Same for planes, the factories were not at the front so no direct to combat phase. Shuttle pilot flies the plane from factory, not fighter pilot.

Some people make websites and others make posts to push agendas. Late war Germany didn't have fuel to get all their planes flying, new or old.

What -data- to base reliability figures on? Sometimes it is there for some countries and mostly it is not. Loss figures alone, combat or non-combat don't cover it as they factor in weather, training and fatigue with mechanical reliability.
Yet crash site examinations were on occasion enough to determine design flaws which is why there was so much flap over crash site souvenir collectors.

I would think that pilot-wise, having to fly your mission in some other plane than you expected because your regular planes are grounded due to investigation or repairs/upgrade would be more common that to be the 1 in many-many whose wings fell off. That would even provide some variation to the game.