That's a fascinating question. I understand what you are saying, but I have not heard that suggested before.
Do you really have no specific needs for higher resolution? If so, what are you monitoring?
As a general rule of thumb, if you are covering an area wider than 10' / 3 meters, you are going to get material benefits from using HD over SD. And since almost everyone needs monitoring more than that, the benefit is clear. See: Shootout: Megapixel vs Analog Cameras
Often higher megapixel cameras perform worse in low light compared too lower resolution models of the same generation., so going with a lower resolution camera will perform better.
Yes, higher resolution cameras are often newer generations, but come with drawback. Choose a camera that is a current generation, and the lowest resolution for your needs. This will keep costs and storage/bandwidth down.
The only advantage is being able to later on up the resolution as needed (such as infrastructure or recorder upgrades).