If you have programmable keyboard then it's trivial to throw numpad into a layer if you so wish and avoid the ergonomic problems of conventional numpad. Especially if you have ortholinear layout then the difference between real numpad and a layered one should be small.
Overall the ergonomic trend seems to be towards reducing wrist movement, thats why layouts like Corne are relatively popular, you can basically keep your hands at "home row position" all the time.
I do also think that numpads are also simply just less useful today than they were 10 or 20 years ago. Back in the days lot of data was still on paper or some other disconnected form. But these days? Where are you getting all those numbers that you are entering on numpad? What numeric data are you handling that is not already on your computer? I really do believe there has been shift in workflows so that people are far less typing in strings of numbers all the time.