This is my real worry with any Google product these days. I know most people think it's a played out reaction, but it's a very real concern, especially for something like this that requires a real commitment -- this isn't just me losing my Google Reader app.
EdTech is booming, and there is a lot of money to be made. Google Apps for Business is booming. Google Apps for Education, likewise, will boom in the same way.
If you seriously think Google Drive or a Google Docs is going anywhere because your precious Google Reader disappeared, you're nuts.
And that was kind of my point. This would be much, much bigger of a deal than Google Reader. The may not shut Drive/Docs down, but they could fundamentally change what they are offering under this Classroom umbrella. Or change pricing structures. They did this with "Google Apps for your Domain".
OTOH Larry Page doesn't care at all about something as trivial as a widely-loved RSS reader while education is something he cares about deeply.
Also, there is obviously a gigantic market there.
That was simply a quick example. Perhaps a better example would be Google Health. You could argue that there is a gigantic market there, and that was killed.