re: How much would having a pension keep you at your current job.

You're right the pension itself doesn't reward seniority, but it's the whole mindset and culture it creates. If you have to stay at a company 30 years to get a pension, people tend to stay that long. With that, you get a whole class of people who come to believe advancement should be based not on individual merit but on "service to the company" or how long they've been "waiting in line." In addition, employee mobility, which pensions discourage, shifts bargaining power to the employees. If an employer knows you'll never leave because you want your pension, they're less likely to compete for your continued employment, in which case disgruntled lifers begin reverting to things like seniority in order to bargain for advancement for themselves.

The first thing any pensioner at my company will tell you when introducing themselves in a professional context is how long they've been with the company. That's great and the dedication and loyalty are admirable, but your 30 years of sitting on your arse may not be as valuable as a new employee's diverse experience and skillset. But God forbid you tell a person who's been at a company 20 years that the guy who's only been there 5 is actually more qualified.