I think that is right (I can't claim much specific knowledge on camera lenses though), it used to be especially bad with the whole "megapixel wars" a few years

I think that is right (I can't claim much specific knowledge on camera lenses though), it used to be especially bad with the whole "megapixel wars" a few years back. Pixel resolution increased, but image clarity didn't, and you would get much better images on old low-megapixel cameras with relatively high-end lenses than with a cheap but new camera of approx 4-8x the resolution in pixels. However, nowadays I am quite amazed by the picture quality of the average smartphone camera. So maybe something changed? Still, we're talking about better lenses/quality than smartphone photos. They may be sharp, but that comes from the advantage of being up close and coming in huge numbers. And in addition to the lens, there's a lot of other expensive parts in a security system, that may need to be replaced or reconfigured because it is all integrated with the current low-res cameras. The bigger such a system is, the more expensive it becomes to change it all up when better tech has come around, even if the new parts are relatively cheap by themselves.