Maybe we're not comparing the same "very rough surfaces" as mentioend in the first post, but I don't agree for one moment that a thin layer of neoprene and a pannier provide nearly as much isolation from bumps and vibration as a backpack and the soft suspension members and shock-absorbers of public transportation vehicles.
Hmmm, suppose I could test my theory with accelerometers....
"Jostled". Getting on and off bus/train, bumping against seats and pillars, trying to squeeze past people to get on/off, running for said bus/train etc. Not just sat in backpack as said bus/train rumbles along.
I wouldn't take a laptop in either a backpack or pannier in just a "thin layer of neoprene", it would be a decently padded sleeve or case. But as I alluded to, the risk carrying it in a thin neoprene sleeve is impact with other objects in the bag, not the vibrations.
What kills electronic devices is high G impact and higher frequency vibration, not the kind of highly damped jostling it would get in a good case: dedicated laptop case, or commuter backpack or pannier with a designed laptop compartment.
However, the panniers are normally securely fixed to the side bars of the rack or bike frame so it still gets some vibration
I'm not sure if we have the same sort of panniers in mind. The only way I could imagine the vibration you describe is if the pannier was a rigid box. If its structure is basically a reinforced bag, the contents are highly damped from the frame vibrations. It will be subject to larger amplitude but "softer" bouncing movements but not high G shocks.
I've commuted on a combination of public transport and bicycle for about 10 years with a succession of laptops, zero issues from vibration or damage.
The whole point of a laptop for work is you can take it anywhere, so wherever you work you have the same machine and configuration. Yes, in some cases people can work directly on home devices. For other cases there are VDI, VPN and cloud storage solutions which are viable. However many organisations don't allow their data to be accessed on personal devices. Many block removable storage completely. A corporate issued, encrypted laptop is by far the best solution for the vast majority of cases where work outside the office is sanctioned (home, other office sites, client sites etc). And as long as reasonable precautions are taken, carrying it by bicycle is simply not the issue people make it out to be.