@Byallmeans
First off, you wrote that 67% of Italian teachers were over 60, when you actually meant that 67% were over 50- that clears that up.
Also, my understanding from what teachers have posted is that teachers in England who were shielding do not now have the option to be signed off on the grounds of vulnerability in a pandemic. The only option is to take sick leave, and this is subject to various HR reviews and measures. Even leaving the job on account of risk would be difficult unless put into motion a term or so in advance.
The Italian system does seem to allow teachers to be signed off, even if it takes 2 doctors, so that seems to have more leeway (though I am not an expert on how this works).
Also, the rationale for spending 2.9 billion euros on preventative measures in Italian education was fear. The whole nation were very afraid because they were hit hard and early, their health service was overwhelmed and they suffered a great deal as a nation.
Accordingly, when it came to opening up, they took preventative measures in schools extremely seriously and devoted considerable thought and planning to getting things right.
However, since this was being executed against a background of pain and fear, it is really understandable that Italian teachers, many of whom are over 50, are very wary about putting themselves at risk again.
This does not however prove that their preventative measures were not worthwhile. These measures are not primarily there as a cosmetic exercise to re-assure the teachers (though you'd hope they would help). They are there to make the educational system work safely and to limit further spread of infection.
I am really pleased that Italy seems to be doing well, up to now, numbers wise. Apparently, having lived through a very difficult spring and summer, the naturally individualistic Italians have abided very carefully by government advice. wearing masks etc. Good luck to them.