My friends that started with me and still are there are in their 16th year of service and still wear 3 stripes - and they are not the first on the seniority list for upgrading.
Rest is more or less correct.
Reason for need of more crews is that they are expanding, mainly long haul, after a long phase of reduction after the SR grounding. Ab initios go on Swiss European Avro while if you have experience you might start on the A320 family. But with experience the salary is a bit low.
Dani