Sometimes I think employers try to offer "perks" because they are cheaper than offering real incentives, like group insurance plans and retirement help.
I worked for a webhosting company recently called WestHost in their support department, and one of the things that they would do is advertise to potential hires "we offer free pop, and LAN parties!" Then, they would hold this over our heads, and if we didn't perform perfectly and clean up management's messes and smile all the while, we got no LAN parties and they acted like we were not deserving of the free pop.
Oh, and did I mention that they paid us jack crap?
I really would rather be paid more and have no extra 'perks' as long as they treated me right. I will always be willing to work my tail off for an employer who does that.