To me 1500 hours does not seem an unreasonable minimum for someone to be occupying the RH seat of an airliner.
Any "airliner" today is going to have
- turbine power
- pressurization
- the ability to operate in icing conditions
- the ability to operate in a high-traffic environment
- the trust of at least 40 passengers who bought a ticket on an "airline" because they believe it infers a certain minimum standard of safety.
Throughout a pilot's career, he/she is going to periodically face situations that require a combination of skill
and experience to achieve a successful outcome. Lots of this stuff just can't be taught; it comes only from learning in the real world.
Having experienced training in the US, I can only suggest that over the past 20 years the standards have declined under pressure from costs (those same bean-counters who forced down wages).
There still remain many, many opportunities in the US for pilots to acquire the 1500 hours necessary to make it to the right seat of a jet, or turboprop. Remember that when the regional industry began in the US (not that long ago), those carriers were operating simpler (by comparison) aircraft such as piston twins, carrying fewer passengers over shorter distances.
As for this opening the gates for non-US pilots, don't hold your breath. There are thousands of US pilots working overseas who would love to return home.