The problem here would be that in most of Europe, there isn't a GA scene or market for pilots to build up to those 1500hrs. And besides that, you always have to remember that experience does not equal safety. I've flown with enough experienced idiots and inexperienced good pilots to say that that holds up. In my opinion, that 1500hr limit is mostly just an arbitrary hoop to jump through, and the focus should be more on filtering out the idiots during training by regulating flight schools in better ways and simply banning pay to fly programs in any form. That would benefit everyone; less pilots get dumped into the job market, average quality of pilots goes up.
I've flown with FO's fresh out of flight school on their first job who have been absolutely awesome and would be a welcome addition in any airline, but who would run into an arbitrary wall if there were to be a 1500hr rule over here as well.