It always bugs me when people (usually sales people) say "It's all about sales. Everyone in the company needs to be selling all the time, not just the sales and marketing department."
Before anyone gets the wrong idea and starts jumping on me - I am not disagreeing with this. But I don't think it's the whole picture, and I don't think it's the most useful way to think about it.
Take my company - we have sales and marketing, product development, and customer support. To me, they're like three legs of a stool. Does it make sense for one leg to say it's all about that leg? All three legs are essential. Take away any one and the stool will fall over.
Part of the reason sales is seen as primary is that they bring in the money. It's pretty obvious that's an important role. They have the most direct link to the success of the company. But just because the other roles have a less direct link to success doesn't make them less important.
Think of fighting a fire. The fireman holding the nozzle of the hose has the most direct link to spraying water on the fire. But without the rest of the hose, and the source of water, he would be out of business.
Take Apple for example, obviously great at sales and marketing. But are they "all" about sales? Where would they be without great products?
A good marketing and sales group sometimes think it can sell anything. (And there is some truth to that.) But when my company has tried to sell third-party products it has become pretty clear that if the product doesn't have good development and good support then in the long run, it's pretty hard to sell.
You don't usually hear "it's all about customer support" or "it's all about product development". To me, those views would be just as incomplete. For example, 37 Signals claims they have no marketing people. That may be true in the sense that they don't have anyone whose only job is marketing. But get real, those guys do more marketing than most marketing departments. They're certainly not "just" programmers.
Perhaps another reason you hear "everyone needs to sell" more often is that non-sales people tend to avoid selling. Whereas sales and support are usually more than happy to talk about where the product should be developed. Another weak spot is that programmers tend to avoid customer support (I know I did!).
While equally incomplete, I think there's value in the idea that everyone needs to do customer support and everyone needs to do product development, just like there is value in the idea that everyone needs to sell.
I think what it boils down to is that everyone needs to keep the big picture in mind, not just any one particular role. That's easier and more obvious in a small company. Most of the time I think my company does fairly well at this. Sales and support contribute to product development, programmers and sales help with customer support, and yes, hopefully everyone helps sell.