Different hoops spread out over much more of a career and ultimately, different education systems and styles.
Immense GA, exec and regional market to weed out and normally a 4 year degree to progress to a jet airliner. Any jet driving major carrier pilot deserves immense respect - those of us who've done an FAA oral for a complex aircraft will attest to that.
Trainees from the UK and elsewhere hitch a bit of a free (freedom of information derived) ride at the early stages of their system - we get over all the big hurdles (fATPL and I/R) before we even get into the market.
Different that's all - a much easier lead in - the real slog to make a decent living comes later for Americans.
Regards
Rob