So I'm curious, are you for or against age discrimination? (see your bolded, and apparently conflicting wording)
Not all seniors are dinosaurs so as long as they contribute to the company. I see no reason to pasture them. A blend of young and old can be a blend of experience and new ideas. The doorstops I refer to haven't updated their qualifications and don't don't have a life outside of work.
The problem is the ones that have so many years of seniority that it costs a ton to can them. You can dismiss a person without cause but it costs a bundle.
Another side effect of over protective labour laws is the trend to contracts. The employee doesn't get fired he just doesn't get renewed.
I often see retired VIP's as members of boards of directors where they make mountains out of molehills because they have nothing else to do.
The movie "About Schmidt" is kind of creepy true for some.