5 years behind becomes 3 years behind. China is expanding their manufacturing abilities faster than the US. Soon they will surpass the US. Look no further than their generic consumer electronics manufacturing.
It's not 5 years behind, engine tech is more on a ~15 year cycle, or even more.
CFM LEAP, latest short-to-medium-haul airliner engine from CFM (GE+Safran) is from 2013 (first run). Its predecessor, CFM56, is from 1974 (first run) and saw a few evolutions, including as late as 2009.
