Well, no. If you're a developer or development manager working 70-90 hours a week developing and/or managing other developers, when do you have time to evaluate the market, keep track of every single competitor and potential competitor?

Do you run a spreadsheet loaded up with market data and demographics evaluating the potential revenue impact for all of the features you're thinking of including in the next release?

And so on and so forth. Product management is a full-time job on a substantial product. It may be that in small start-ups people wear many hats and you don't need it as a separate function. But if your team ever gets to the point that you can justify a full-time development manager, your team probably needs someone else with nearly full-time product management responsibility.

In addition to that, there are sometimes some benefits to separating product management from development management. Sometimes. Being a little divorced from the product's inner workings can provide a certain useful perspective. Hopefully, the product manager isn't wedded to the feature that a developer just spent three weeks building and can jettison it to ship on time :-)

Actually, I was at Microsoft between '94 and '05 and that's close to what happened in many cases, but not because of a single program manager. (At least not in cases that I saw directly.) Rather, as the company grew, and more program managers and project managers were assigned to things, a lot of developers felt less in control of their work due to the collective influence of a non-programmer organization.

That kind of growth probably has to happen. To be fair, most all the program managers had engineering degrees, and some had been successful developers. The project managers came from a different track entirely, and I think that was a more challenging relationship for a lot of developers.

If they had a problem with that sort of thing, then they shouldn't have taken a job at Microsoft, or even a corporation of modest size. Division of labor, and all that.

Besides, for a great many developers, dealing with a PM is better than dealing directly with people in finance and marketing, or customers themselves.

"program manager" title has a long of history, it existed way before Microsoft was around. In the 1st half of 20th century, the common use of the word "program" was to describe an allocation of resources like manpower, production capacity, equipment, typically in the military setting. For example, the term "linear programming" as a mathematical optimization technique is based on using "programming" in the sense of allocating resources.

So historically, program managers handled decisions about how to allocate resources to accomplish a mission. These days, program managers usually allocate resources over a portfolio of projects and decide whether projects are helping to achieve the program's mission.

Product manager has a responsibility for one or more products and associated strategic and executive decisions , around business plan, marketing, sales, research and development.

If the only reason people pay attention to you is that you have the ability to fire them, you aren't much of a manager. I worked for years as a team lead. I had no authority to fire anyone, or dock their pay, the most I could do was to say nasty things about them like "They have their own independent ideas about how to get things done instead of genuflecting to me."

If he was a good program manager, people would have respected what he did, which was to understand the market for the product so well that he could inspire and lead the team to build the right thing at the right time.

Depends on the company. Since a Program Manager sits above multiple projects, some companies think of them as just a coordination role -- a little more than a PM but not yet a director. But other companies think of them more like super-PMs, parachuting into their poorer-performing projects and taking over until the PM and the team can get their act together. In these tougher Program Manager roles, they're responsible for the day-to-day life-or-death of the project.

Sadly, more companies are leaning to the idea that the Program Manager is more like a fancy clerk. They end up pretty stressed out and under-appreciated.

This gets to the central question: How do you create, run, and release a huge effort that might take hundreds of man-years, like Office 2012? Something like that covers a lot more ground than simply kicking out some code. There are all sorts of things that need to be coordinated.

Companies are still sorting through how to set up and run programs, in my opinion. There is a LOT of room for screwing things up between 5 guys and 150 guys. There are a lot of tricks to use, but many times people want simple answers and the simple answers are not forthcoming.

A lot of time employees just go to their PM and then go around the Program Manager directly to the higher-ups in the organization. Makes the whole thing quickly devolve into a Charlie Foxtrot.

(Disclaimer: I've done quite a bit of setting up programs and helping companies manage them)

EDIT: I've describe a Program Manager as being "over" the entire effort. Some companies just kick them out to the side of the whole thing. This is an even worse setup, because the business drivers aren't directly connected to the work.