and all the dust will fall to the bottom, lets shut this case and have it run 24/7 for a year without opening the case... if it havent stoped working or your house burnt down its a miracle. it is idiotic to place the power supply in the bottom of the case, period.
What, you mean like the CoolerMaster Cosmos-S case, where the PSU is at the bottom, pulling cold air through a dust filter, venting it out the back and not at all exposed to dust from inside the case itself?
see here