LGA-LAX is a 1-stop (it is actually LGA-ORD-LAX and often with a change of plane at ORD but a single flight number, so counts as 1 segment) and might be seasonal. AA regularly comes and goes with these through flights. It is of course a far inferior service to the nonstop JFK-LAX, if comfort matters.

The Canada exemption is historical and dates back to the IATA being headquartered in Canada. I still think AA would refuse to write this ticket in Canada (only the airline flying the first international OWE leg is required by OW to issue the ticket, for other airlines it is optional). AA in Japan will issue it, of course (even though they are not required to).