Why worry when the US is naturally superior in all things...?
Because they've consistently spent >$50B per year on R&D over the last decade since the last product came out(F35).
The progress made in terms of avionics, engine and weapons is much more matured than anywhere else.
In simple terms, after cold war ended, the procurement took a hit, but S&T, RDT&E kept on going at the same pace. Most advanced unfielded tech was advanced to TR Level 5 or 6 and then simply packed up. This allows for quick( less than a decade) employment of such tech into newer platforms.
Albeit, all of this is only useful if they have that aforementioned 'decade' available to implement these technologies. It is the duty of Air chief to ring the bell when he thinks the service might be challenged in a decade.