Again I don't think it declines because of a single person. I do however think that the executive person has a lot of influence on how the us manages. There is a reason so many staffers were freaking out because key positions were unmanned more than a year after Trumps inauguration. They were freaking out because he did not follow security briefings, because he mishandled diplomatic engagements and because his cabinet was constantly shuffling. Pretending like these thing were inconsequential seems "ubmaterialistic" to me.