Any turbo will raise intake temps no matter the boost you are running. You compress air its temp goes up no matter what you use to compress it. You use a hot turbo to compress air the temps go up more. According to your theory every single turbo car ever made would be out of its efficiency range.

 

And to some people that's worth a blown engine

 

I was saying that under the assumption that people would have an intercooler adequate enough to handle said amounts of boost...