Earlier quoted context omitted.
Re job security - In reality as long as you produce value it is just as secure as a perm job. Also, psychologically I think it is more "secure", ie. there are no surprises. Companies hire you for a reasonably well defined task and term, hence you are fully aware how much you will earn during this period as well as when you will have to find your next gig.
This is changing. The other week every LN contractor at my company was told they are getting a pay cut. Contractors have also been first to be let go. The last 10 years, yes. The next 10, not so sure.
What I've said above is of course anecdotal based on my circle's and my own experience, but when looking I was never without a new contract longer than a couple of weeks in the last 7 years. The next 10 years... I don't know, however another advantage being a contractor in my opinion is that you have more opportunity to be exposed to and learn new stuff, which helps staying current.