Interesting thread that reminds me the two different views that exist among quantum physicists on force carriers: the one of the dominant Feynman school (represented here by THHuxleynew ) who infer that perturbation theory and with it virtual particles are universal and apply at all time/energy/distance scales, and the one who realizes the limitations of SM, with force carriers being only a construct of perturbation theory that only applies to high energy particle physics and fails in low energy QCD, bound states, solitons, etc.., which actually represent most of our universe.
When a new order calculation using perturbation theory leads to a change of several hundreds percent in cross section values, I do not applaud the result (which may be beautiful from a mathematical standpoint), but put into question the physical meaning of the underlying model. I'm a big fan of the like of Hestenes, Barut and Schwinger, much less of Feynman, and still less of where SM is leading us today. In French we have an expression "fuite en avant" that applies so well here.