It would kind of be good if this resulted in new buses needing double glazed windows for rigidity - as they improve the environment so much by preventing steaming, just as they do in houses. It would add a lot to cost though.
Even some cars have double glazed side windows now and it does reduce steaming (my previous car, a Ford Kuga, did).
Would be a while before it got to school buses, though, as these are invariably old tat.
I do wonder how much you use the bus, or indeed are aware of the cost pressures the industry deals with? Because some of the things you repeat regularly have little to no resemblance to my experiences as a non-driving, regular bus user.
Where do you imagine the funds for this extra cost are going to come from? Exactly where do these double-glazed buses run? (because the Citaros I travelled on in Germany when I lived there would steam up just as much in winter as the E200s at home). Indeed, I can think of plenty of double-glazed houses that still steam up inside because of other insulation pressures (and how much of that do you think there is in the sides of a bus?)
The only time I've been on a bus that smelled of "wet dog" recently was last night... when a wet dog got on with its equally wet owner for three stops part way through the journey.
As for "invariably old tat", that would explain why the school bus that runs past the bottom of the road is just as regularly an 18-month-old E400 as it is a 10-year old E400, if not more so...