National vote should be favorable for the president

This chart in the New York Times December 16, 2019, partially replicated below, shows in lighter colors the states where job growth during the last three years has been very low. The five outlined states are described as swing states, crucial to Electoral College victory. The chart makes it clear that the economy is so strong nationally that the president should have a cakewalk to re-election, but the swing states are lagging and for that reason his path to success is more pockmarked. Why does he support this system?

swing state economy map.png