Let's see if your limited english understands this sentence then...
"How much taxpayer money should be spent on searching for a conclusive answer for this event, especially when there is no reasonable cause to suspect additional foul play?"
Simple, isn't it? If there is no reason to suspect domestic conspiracies, then the time and money spent should be sufficient to conclude the general cause for the collapse of ALL buildings were the airliners. Even if it cannot be ascertained what the definitive cause was for the collapse of #7, it does not follow FEMA has no idea, nor are uncomfortable with their investigation.
You have alluded, hinted, and indirectly stated there is a coverup of some sort. I am not putting words in your mouth, you are saying it.