Technical question about self-cleaning ovens & high temp cooking

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My stove is a ceramic/glass-top Kenmore convection, got it last year.

I just ran the self-clean feature as it was getting a little smoky during heating (just from dripped cheese and all the other crap over the last few months).

Self-cleaning ovens crank up to 900 degrees to burn the junk into ash. I don't know how hot mine gets but I'm guessing it's close.

My question is, if the oven is capable of hitting 900 degrees, then when doing regular cooking why am I limited to (usually) 500 degrees? Lots of people would like to make things like pizza in high-temp ovens, which they don't have at home, and yet the oven is obviously capable of running at a high temp for hours, so why isn't this an option? Are there average-price-range home ovens (under $1000) that allow you to do this?