shouldn't the fuse system stop a motor short or motor fail on blower motor?

What is your question?

I had my truck running for two minutes when I smelled something burning. I realized the A/C wasn't working and opened the hood. saw the compressor working fine. Got back inside, shut off the A/C system and saw smoke coming out of the dash, grabbed a shirt but it was too hot to put out the hot melting plastic. So luckily I had an extinguisher and put out the fire in the dash and floorboard. So why didn't the fuse system prevent this?