Realistically, you're going to end up with some small ROI. Let's suppose you end up with a 1.05 ROI for the company. For every dollar the company spends on you -- not just your salary and benefits, but also the cost of a desk for your butt and a manager for your ass and an HR department to cover their behinds when you start thinking too much about your coworkers' -- then they make a $1.05 back. If your company's owner has a hundred employees, he'll make five times as much as you, for doing nothing but owning it. If they employee ten thousand people, he takes home 500x your pay.
Why do you think your employer deserves more? Why should he get a 2x or 10x ROI on your labor?
For all the years he ate pasta. But that doesn't mean you don't deserve your right pay too.
For any positive value of Z, there will always be another employer willing to hire me where Job Security = Z1. Z1<Z. Thus in a good market the value will tend to zero.
You are mistaken to think that Company's profits is a the sum of value added by each of the employees. I would say company's real profit should be the additional value generated because of synergy between the teams. For example few ordinary individuals can deliver extra ordinary results as a team.
But I disagree with tn13 too - I'd try to extract X^2.
Your job security = value to you add to the company - what you are paid.
Make sure it is 0 at all times. Or have some written assurance from the employer (such as stock options) that the meager pay now will be compensated for later.