Like having your stock options to vest over a five year period?

Also, in many many fields less meritocratic than software, you typically gain privileges as you accrue seniority with little regard to experience or actual contribution.

I meant having bonds on employment - imagine having to pay your employer when you quit because they had no idea what they were doing or flat out lied about what the job would entail? The thought is horrific.

The fact that you don't have to take actual cash out of your pocket to do it makes it a much simpler/less disruptive thing to do, but the outcome is the same: You commit to work for the employer for a set number of years, and forfeit a sum of money if you renege on the commitment.

This assumes that you are guaranteed a promotion/autonomy/responsibility after a few years - how many contracts have promises of career advancement in them (not the "social contract")?

It's actually pretty common: http://en.wikipedia.org/wiki/Seniority

> how many contracts have promises of career advancement in them

It's extremely common in union contracts.