How can we have an intelligent discussion about the Cost-Effectiveness of older programmers vs. younger programmers without a method to measure programmer productivity? The only thing measurable is the "Cost." The "Effectiveness" part is left out completely. When you come up with a generally accepted method for measuring programmer Effectiveness, please let us know. Until then, I predict, anti-old-programmer bias in hiring and layoffs will continue in most organizations.
How does an individual programmer deal with this bias in her own career plan?
Option 1: Burrow deep into a niche technology upon which one or more corporations depend for tens of millions (or more) dollars in profit. Ideally this niche technology will be as attractive to current CSci students as learning COBOL is today. Show up for work everyday. You'll have employment opportunities well into your 70's.
Option 2: Start a small business. Software businesses have notoriously low start-up capital costs. If you can identify an unmet or under-served software need of a number of small or mid-sized businesses and work with potential customers to come up good solution, you can create a business that will feed you and your family until you no longer want to work.
Option 3: Bag groceries, deliver pizzas, work seasonally at the post office or in retail or try real estate or insurance sales or used car sales when you're 55 trying to survive to 65 and Social Security/Medicare.
I've seen a large number of techies (not just programmers, but Engineers as well) choosing Option 3 by default because they didn't want to stare the grim reality in the face.