I can grok the ideal you have, but honestly, I think that it would be a huge morale-killer.
Think of it this way: You get hired on, and you do great work. But then, you have to always be mindful of company politics, and be sure to kiss the right asses (and stab the right backs), else the next periodic review may well see you on the street in spite of your contributions. I've worked for companies that did that, and everybody was constantly either worried about keeping their job, or were busily trying to sabotage their buddies in order to secure their own careers.
It would be akin to working on a renewable contract, truth be told, and if that's the case, then you may as well work for them free-agent and pocket the difference. Another analogy would be that it's like stack-ranking, but more aggressive in parts - each department would have to constantly justify everyone in it, and they'd have to fall to something like stack-ranking in order to keep tabs on who stays and who goes when word comes down to jettison someone.
Now I've seen the opposite as well - Fiserv (the web banking software company) has a nasty habit of doing layoffs every two years -- often with no rhyme or reason other than to make the numbers look good. At the appointed time, they demand that each department chop x% off their department headcount no matter how over/understaffed the department may be; it's become so routine that many employees term it the "bi-annual layoff lottery". Again, total morale-killer and team-killer.
With an eye towards all that, I propose something kind of radical here: I propose that companies look to hiring with an eye towards adaptability. That way, should a product or project either go sour, or should times change, odds are good that unless the company is hit/hurt overall, you can start moving folks to new projects and/or new product lines, giving existing employees priority for those slots. It wouldn't hurt to have solid mentoring and training cultures (and budgets) in place to help your good employees stretch out a little in their careers, so that they can more easily adapt right along with the company. But that's kind of a pipe dream, I know...
Personally, I've decided to become just as professional, mercenary and ruthless as the employer who I work for. If they're awesome and caring about their people, I'll be awesome and caring about them, and go above and beyond for them.
If they're a bunch of back-stabbing and self-serving asshats out to chase the Almighty Dollar with no regard for their employees' morale and careers, then I have zero problems with doing only what is required, moving to a better job elsewhere with only a 2-week minimal notice, and not really give a damn if my departure leaves them in the lurch for anything critical. I've happily done so before, then watched months later (via the grapevine) as they spent a massive amount of money not only paying for my replacement, but in cleaning up the damage from failed projects due to multi-month disruptions from having to find someone and then getting that someone up to speed.
Until that large awesome company exists that you would give an arm and a leg for? Well, you have to look out for yourself, and in the tech industry, there isn't exactly a lack of jobs for those with the skills and the drive to take them, you know?
