OP - interesting post. This is a perfect example of YMMV. I have never found SG to be laid back and with re-org after re-org I've always felt a sense of uncertainty. I think, for you personally, you may have not been affected so it doesn't seem that way. As far as security when you do your job well - I've seen ppl terminated for simple mistakes. Sometimes it was merited, other times, it just seemed like a method to reduce staff. For awhile I worked in a culture of fear of consequences that might occur for making a simple mistake.
I haven't found my experience to be very 'even' - sometimes things are smooth and somewhat in control. Then there's a re-org and it's total chaos. The dust settles, everyone's adjusted to new roles, a new direction. Then bam, there's another re-org.
As far as security goes, in another post it was suggested not to make large purchases. I have been in that mode for the last 3 years.
If you've been in a stable role, then good on you - but it hasn't been my experience.