[Kirby64]

It already has, if by low end professional you mean low end dslrs in general. The low end of dslrs was largely a way to get good quality images for your typical non professional person. Tourist, enthusiast, etc. Nowadays, why bother? Good phone cameras have been plenty good for many years, and much more portable.

I don't think they'll likely ever replace professional gear, since any tech in phones can easily be applied to cameras on a larger scale... it just eats into the market more and more until professional is the only market left.