I actually agree with this statement and to your credit, a lot of the design work I do follows some of this.
Keep in mind that these are factories on wheels which means not only do we consume a tremendous amount of data, we also generate it. For example, 3D maps are built on the fly to show the customer where product has been sprayed, seeds planted, etc... On these vehicles, it's quite typical to see 1GB Data/hour generated which for an embedded device with no traditional hard drive, that's a lot. Flash memory is susceptible to extreme heat/cold so we have to be creative in this regard too (I can't talk much about this but suffice to say it's challenging).
That being a case of many, there is always a trade-off between performance and what you can reasonable keep separated either within the same PCB or between separate modules.
Thus, as much as I would like to keep separated, you simply can't sometimes. Current state of the art only allows for so much.
Keep in mind that these are factories on wheels which means not only do we consume a tremendous amount of data, we also generate it. For example, 3D maps are built on the fly to show the customer where product has been sprayed, seeds planted, etc... On these vehicles, it's quite typical to see 1GB Data/hour generated which for an embedded device with no traditional hard drive, that's a lot. Flash memory is susceptible to extreme heat/cold so we have to be creative in this regard too (I can't talk much about this but suffice to say it's challenging).
That being a case of many, there is always a trade-off between performance and what you can reasonable keep separated either within the same PCB or between separate modules.
Thus, as much as I would like to keep separated, you simply can't sometimes. Current state of the art only allows for so much.