I think there is a space issue and a speed issue at stake here as well. The physics of the flight model and the graphics currently take up 2GB on my drive and I have very few addons. Add in the crash physics and the extra graphics for exploding buildings etc and you will get a much larger package.
In addition we have a speed issue. Look at the cfs series, you always get a slowdown in performance when there is an explosion on screen. You are creating a graphics intense envioronment which many systems have trouble with.
As far as I am aware most FS users report FPS drops when close to the ground in any case, add in the crash effects sub programming and you will probably see an even greater drop.
Also this isn't a video game it is a "serious" simulation. I have never flown for real other than as a passenger so I cannot comment on realism but I would point out that for many pilots a crash is a non survivable situation. The pilot (ie you) wold not live to see the "cool" flames that are immolating him. I'm not trying to be holier than thou about this. I have quite merrily burned countless thousands of virtual people since the days of Syndicate (Amiga version

)
My final point is that when I crash I want to reset the situation again quickly so that I can try again. Imagine a competition like the current "Fly under the space shuttle". At the moment you have crash detect on and off. I have it on, otherwise it is cheating. If I had had to sit through 30 seconds of "effects" each time I messed up, I'd still be trying....

I do agree that we need more "stuff" going on with wear and tear. I switched the sim to max realism and endless fuel the other day. I put the park brake on, the mixture to full rich and the throttle wide open and sat on the ground and maximum time compress. I then went to work.
40 minutes travel to work. 10 hour shift. 40 minutes home. The engine was still rock solid. I reckon that no engine can go for a few weeks at full throttle and not develop a few "issues".
So there you have my thoughts. Disorganised as per usual but what the heck.
Will