One of the major difficulties in this profession, compared to Law, Medicine etc is the pernicious seniority list syndrome.
Encouraged and promoted by the unions it has destroyed mobility and career progression: until company lists are eradicated nothing will change.
When you have to start from square one, again, it inhibits free movement of labour and progression: if, when you were handed your ATPL you went on a pan European seniority list ( being as we are all under EU Ops, it would level the playing field and stop Air France,KLM and Lufthansa insisting that you speak French, Dutch, German.
It would also allow you to move from Company A to Company B at the same seniority level and salary.