Totally agree here with the part where "it’s foolish to actually do unnecessarily complicated work"!
But I'd say the ultimate job security is being known as someone who creates real value to the organization, and the way you do that is by putting in extra effort into understanding and communicating the business value of your work.
for example: the latency reduction is not just a latency reduction, it's an increase in x% in revenue.
I would say that it is more about how coupled your field and the product you are building are with it being implemented properly. For some areas, like most of the web or building SaaS, it is not as tightly coupled as for other areas like system engineering, building high-performance products, etc.