First it is generally a tough problem. There is more room at the bottom than there is at the top. Many people become entrepreneurs because they don't see any way up in the firms they work for.

At a big company you might feel you are not making a big impact, as for stability, all of the time I see headlines like "Intel lays off 10,000 engineers."

Feeling bitter about things won't help you get a job, at least if that attitude comes across in your communications with them.