There are already hundreds of qualified ATPLf holders eligible to work in the UK who do not have an airline job. Someone estimated that CTC alone have 130 cadets in their system. How many will graduate from the Integrated schools this year? 200? + all the others from modular schools, probably at least another 100 + military. Enough to take the requirements for new pilots of many airlines for many years.
How many Australian, NZ, SA and Indians have the licence and can work here? Hundreds. Add to that all those EU member countries.
My airline has 300 pilots, for 32 aircraft, Monarch a similar number. There aren't the jobs available to absorb the number of 'eligible' candidates, and the boom times are unlikely to return in such a saturated airline market.
There ain't ever going to be a shortage of low-houred ATPLf holders. Never has, never will.
If you're waiting around for a sponsorship to start, you will be waiting for a very long time!