I agree that the 1500 hour rule isn't going to solve anything but it does stop the airlines from abusing the system just a bit. Starting pilot flight time really isn't the problem.
1500 hours in a single engine teaching kids (probably foreigners) is tough work and builds solid experience but it doesn't make you an experienced airline pilot.
The reality is that if the regional airlines raised entry level pay for first officers significantly, suddenly people with 1500 hours would no longer be competitive for those jobs so they'd be spending 2500-3000 hours instructing instead of 1500 hours. There's plenty of higher time pilots that would take the jobs instead.
This is actually how it used to be....20-30 years ago people with 1500 hours didn't get hired at regionals (flying 19 seat turboprops) and those that did got paid better than new hire RJ co pilots today (adjusting for inflation). They also didn't expect to spend more than a few years at the regionals since they only made up about ten percent of the workforce.
In other words...we didn't need a 1500 hour rule back then because the regional airlines didn't hire people with such low time anyway.
I'm advocating a free and open market where new pilot pay is based on market rates which will always be rock bottom for someone who has no airline experience.
But I think that the airlines should be free to hire pilots at any experience level and at higher pay to attract them without those higher time pilots being lumped into the same new hire category as the zero time pilots.