I imagine that the USA is about the only possibility for GA or even junior LCC crew to improve their incomes. The E3 visa program is a gift to Aussies, and it seems that the US will need thousands of pilots for the foreseeable future, with potential for a permanent residency and a legacy carrier job. Others may have the right to work in Europe or the UK, but I think the pay & conditions there are pretty poor.
I don’t know how many LCC F/Os here would emigrate to join the bottom of an E jet list despite the rather more interesting follow on opportunities. As the saying goes: “It's hard to make predictions, especially about the future”.