For all but a very small minority of people at the top, the corporate world is a cult of youth. The 'up or out' mentality favours younger employees, if only because they have more rungs of the corporate ladder before them, have fewer competing responsibilities, and are cheaper. But as a communicator I know that messages that resonate well with one audience (in this case, shareholders), don't necessarily meet the needs of others (such as society, local communities, employees), or indeed benefit the company itself in the long-term. That's why some enlightened companies are adapting to the challenges and even benefits of an aging workforce.
This seems to be particularly common in journalism businesses, where the number of 40-plus people in the companies is often significantly lower than the 20 to 40 bracket. Some of them take the PR shilling, some of them go freelance (hello!). But what happens to the rest of them?