Let's not exaggerate. It will almost never "dramatically" change the lift. Even a turbulent boundary layer on a typical airfoil is only often several millimeters thick. The displacement thickness is not that much to begin with so it won't be that dramatic of an effect most of the time. Of course there are always exceptions, but in general the increased turbulent displacement thickness is not that dramatic.
That is definitely true of attachment line contamination, but again it isn't the huge effect you seem to be implying. The turbulence is much more important due to its effect on drag than lift.