unless the Finnish school system has bought into Chromebooks in a big way

Yeah goverment is now giving laptops students at that level, on a loan basis. Just so that everybody has access to free study materials that are now partly of fully digital. The computers are usually, but not always chromebooks because they are cheap and chromebooks are the “student laptop” anyways.

I wonder if the whole Secure Boot/Microsoft shim key issue is a part of this.

Yeah that’s part of it. The boot issues with usb. It’s apparently a total lottery of whose computer decides not to boot when the exam starts with the new windows limitations.

I would think any webapp based system is going to leave more room for cheating.

The question is also what would US government do. You miss the fact that windows-x86 complex is self supporting cornerstone of US soft and economic power, also spying. What will they do to prop up that monopoly?