We're seeing a similar situation this side of the pond in the UK. Skill mix on the unit is becoming increasingly junior, staff turn over is getting higher. Some nurses are using critical care as a short term experience to accelerate their career progression into senior roles on the wards or into some advanced practice roles.
When I was a student, critical care nurses were seen as the experts of nursing care in the hospital (I love the navy seals of nursing comment made in a previous post, I'll be using that in the future), it's why I aspired to be a critical care nurse. To those outside of ICU even a short period of working on the unit (6 months to a year) is seen as highly desirable when employing nurses into senior positions, even though it's an incredibly short time in practice as an ICU nurse. In my current place of work, nurses who've been there for two years are seen as experienced, when I'd been on the unit for that long, I was considered as still wet behind the ears.
I guess there's a number of factors at play, it does seem that these days, no one wants to be a staff nurse anymore, but then conditions aren't great for nurses so why would they want to be? I've no problem with people wanting career progression, but it's immensely frustrating to put lots of work into supporting someone to become a competent critical care nurse just for them to leave after a year.