Earlier quoted context omitted.
Plenty of open source options that will teach them 90% of what most people will need to know. Taxpayer money should not be going to these corporations.
Google Workspace is free to schools. Therefore it 'costs' significantly less than running the infrastructure to service accounts for several 100's to 1000's of staff and kids using a FOSS solution. Of course, there are other email providers, but they are rarely free. They'll also still need to put security solutions in front of it, or indeed Exchange Online, because the offerings are rudimentary to say the least, but…
The point is to not pay Microsoft money to promote Microsoft's continued monopoly, which will mean you have to pay them money again next year.
Any school paying for closed source software when they could be funding a company to make open source software is doing it wrong. Same with textbooks.
100s of 1000s of schools all paying for something they won't own and will have to pay for again in the future.