"A Race To The Bottom"

A race to the bottom usually refers to people being prepared to settle for "good enough" when they ought to be striving for best. If I can save money by settling for good enough, then a competitor will try to save more, thus lowering their standard below mine. If I wish to compete I need to go lower than them - and so on, and on - in a race to the bottom.
It is variously referred to as "dumbing down" or "appealing to the lowest common denominator" or "a race to the bottom"