And in truth it is actually a mode of operation that is shared by virtually all industries - be it technology, refrigerators, autos, ship-building, road-repairs, etc.
You'd be hard-pressed to find a business that operates profitably without having embraced parallelism in virtually every aspect of their business units (from manufacturing to R&D).
The reason I suspect we encounter a fair number of forum members who don't comprehend this reality is that, and this is just a guess, these folks simply haven't been exposed to or experienced the aspects of life that bring them to realize the reality of today's business.
I'm not making it an age or maturity thing, but they do tend to be correlated.
If you don't work as a professional, having lived long enough to accumulate the education and the experience it requires, then you probably haven't been exposed to the realities of how businesses operate in pretty much any industry and as such the preconceptions you have in your mind in terms of how they operate are limited by your life experiences which may be little more than the environment at high school or working the floor at Frys.
The point being that it isn't fair to your fellow forum members to expect them to know things they have no way of knowing about, just as it isn't fair to yourself to expect these things to need go without saying and finding yourself frustrated having to repeat them for each new "generation" of forum members.
Think about how often we have the "its econ 101 people, simple supply vs. demand" threads and discussions.
That discussion will happen every year as new members join until the forums no longer exist. So too, I suspect, will the "product development happens in parallel, not serial" discussions. It may be old news, and frequently discussed new, to you but I'd be willing to bet its the first time they've heard of it or spent any time really contemplating it.