Preventing bugs with soundness is not necessarily the best, and certainly not the only, way to reduce bugs. You can reduce bugs by making code easier to read (code review has been empirically shown, time and again, to be the most effective, in terms of cost/benefit, bug reduction technique), and by making code faster to write and to compile, thus leaving more time for tests and other verification techniques.

If sound elimination of bugs were the best way to write programs, we'd all be writing in Isabelle, Coq or Idris, except even those of us who do -- in fact, especially those of us who do -- know that it's not the best way to write programs.