Well...yes. They will fine tune their calculations to be more precise. But they will still use Newtonian Mechanics in their calculations. Newton's laws are still valid in normal circumstances. But sometimes requires tweaking. That was the point I was trying to make.
Newtonian Mechanics are still taught in engineering schools. As opposed to say 'phlogiston theory'.
I guess there is quite a nice analogy here between mechanics and biology. It is possible that the equivalent of general relativity will come along and alter how we see evolutionary theory at the edges and in extreme circumstances. But evolutionary theory is so well verified by millions of real-world observations that our current understanding would continue to be valid under normal circumstances.