> in practice every job where I've been tasked with making something fast, only linear time complexity was good enough.

Presumably you weren't tasked with making something fast, were linear time complexity was overkill. In other words, quadratic complexity may have been fine in many cases, but you weren't tasked to make those fast.

I'm not saying you claimed otherwise, but somebody might misread you as saying "in practice, only linear time complexity is ever good enough".