Simple fact of the matter is, things that are in the general interest (low prices) are not in the special interests (union membership at one level, and having to deal with increased competition from another level).

Low prices are not in the general interest if it costs American industry to achieve them. A nation's real wealth is in what it can create. As it stands right now the US would lose WW2 because we don't have the manufacturing capacity to win a war on that scale.

You'll notice some cognitive dissonance when Trump talks about opening up our markets of prescription drugs to foreign competition (lowering their prices) versus everything else.

Drugs are not a free market. They're an artificial monopoly that's exploiting US consumers. Prices are lower around the world because the US goverment is setup to make sure that drug prices remain high in the US and other nations are more competitive in prices because they negotiate with these companies. In effect the US is paying for the bulk of the R&D that goes into these drugs while other people get them for almost nothing. That's socialism, not capitalism.

Hanging the threat of re-importation over the heads of these artificial monopoly is a good way to get them to stop screwing the public.

He cares about rust belt special interests (steel, auto, etc.) more than he cares about pharmaceutical special interests and more than the general interest.

He cares about manufacturing because that's where the wealth of the nation is. It's not an accident that US trade policy was very protectionist of industry for most of it's history. We became very rich because we developed by massive industry and massive natural resources and both happen in an environment of restricted trade.