Older developers. Is it possible to become a programmer not at 25, but at 50?

We talked with a familiar recruiter - he gave an interesting statistic. He says that after the age of 35 years for recruiters, looking for programmers - lies a hefty statistical pit. The market is very poor for programmers of 35+ years available for hire. He cited several reasons:
1. Often, programmers grow into team leads and managers and are gradually washed out of active development, ceasing to be “just programmers”
2. Many coders at 35–40 cease to keep up with their younger colleagues, feel this and consciously look for a “safe haven”, not responding to recruitment calls to quit and run after an interesting project.
3. Family, children - mobility becomes lower, it is no longer so easy to take and move closer to work, go on a business trip, and so on.

Of course, this view is subjective, it works with outsourcing teams, where the reaction speed and mobility are very critical, but there is something in it.

And then - the question ...
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And I would like to ask a habrovchan - tell me how, in your opinion, a programmer is 50 years less productive than a programmer at 25. I understand that it looks like comparing the flat with the green, because all programmers are different, and there are mega-monsters retirement age, which tucked in a belt dozen suckers, but I want to get some general idea, statistics, or something.

You can even complicate the situation - and how much more difficult is it to LEARN a person with a technical background and a higher education 45-50 years old to the basic skills of a coder than a 17-18-year-old high school graduate. Again, I would like to get an opinion, because the indisputable "depends on the person" - I can give myself.

Finally, I will say that I saw a very positive example of late entry into IT, when a woman of 50 years in half a year became a very high-quality and fast html-coder. It is clear that this requires a much smaller amount of knowledge than “adult” programming, but you cannot throw out the words from a song.

PS I saw a topic on the same topic, maybe you will be interested - http://habrahabr.ru/company/abbyy/blog/103952/ . Inside, there is a link to an article where the opinion is expressed that the peak of human intellectual activity is not between 15 and 25, but also between 50 and 60 years, and a discussion of this thesis.