It's true that the US effectively imports energy via foreign goods, but I don't think that effect accounts for all the decline in US energy consumption per capita.
Carbon dioxide emissions are an imperfect but (IMO) good-enough proxy for energy, since the world's energy supply is still dominated by fossil fuels. If the US counted imported goods toward its CO2 emissions, as of 2016 they would be 7.7% higher:
https://ourworldindata.org/consumption-based-co2
Primary energy consumption per capita peaked in the US in 1978:
https://ourworldindata.org/grapher/energy-use-per-capita?tab...
It was down to 79,056 kWh/capita as of 2015, compared to 98,139 kWh/capita in 1978. If you adjust the 2015 number up by 7.7% it's 85,143 kWh/capita -- not down as much, but still down. That's lower than the average for the 1970s, 1980s, or 1990s. (And China didn't really become an export powerhouse until after it joined the WTO in 2001.)