I have no idea about the US - I can only speak about europe.

Since we're in the middle of a recession, the salaries are pretty down, and a lot of our jobs had been outsourced to cheaper countries, eg India, eastern europe, China, Singapore ... its very difficult to get a job right now when you have some kind of expectations of what you need to earn. This might obviously be better when you're a newbie - but still, open positions are rare, you might get a job when you know the right people, dont even expect a response to your cv.

Best entry is probably Linux since its so easy to get the skills and sufficient training yourself at home - followed by Solaris that is as well available for PC.

But please be aware - having / using Linux at home and being Unix SA in a big company are two very different things. And a mistake made on a production environment because of missing experience can cost your company millions of dollars per hour - so you should be either very careful and doublecheck with someone more experienced what you're going to do than just try and error.

I would always recommend to have some professional training from the Vendor (Sun/IBM/HP) and at least an entry certification before applying for a sysadmin job. Going into engineering without having practiced the OS is not a good idea - you should definitely have reached senior level (5+ years in your OS) knowledge before thinking about ... and even for a normal system administrators position, a solid IT background knowledge (Hardware, Networks and maybe a bit scripting) is recommended ...

Good system administrators will probably always find a job - somewhere. The question is very likely rather what you expect to earn in your job, how mobile are you and how much experience can you bring into your job - but as long as there are computers, there will be SAs ... and the more specific and rare your skills are, the more demand in your area of expertise, the more likely you'll get a well-payed job.

I do not really understand the 1-5 level model - I am aware about Junior SA - SA - Senior SA and SME (special matter expert, as well called level3 - of any special area of expertise - this could probably count as well as systems engineer).

BTW: a software engineer is a developer at a senior level

Kind regards
zxmaus