I'm amazed at the amount of people defending Microsoft here. As many people have said, if you call something unlimited, don't be surprised when someone sees how much of "unlimited" they can actually get!
But I don't think that those 75 TB accounts were the real reason for these changes. Microsoft must be having serious issues if they had to reduce all free accounts to 5 GB. Either that or they think Office 365 subscriptions will soar because people need the storage space. Here's the thing though, cloud services are pretty competitive these days, so reducing your capacity and raising your prices is a bad idea. Apple offers me 50 GB for $0.99 a month, Microsoft is now trying to charge me $1.99 a month for the same amount of space? And on top of that they're not even going to offer 100 GB or 200 GB plans anymore? This is obviously a money grab.
For the people who say "if you're getting it for free, you have no right to complain when it's taken away", I think if Microsoft were really upfront about what they were doing, then the complaints would be a lot less strident. But when the argument is, "Well some paying users took up too much space, so uh you free users now all have less space", it's pretty obvious that Microsoft is not being upfront with their customers.
I use Outlook for email since I wanted to move away from Gmail. They made a big deal about how they don't scan your emails to sell to advertisers. But now I'm thinking maybe I should just upgrade my iCloud to 200 GB per month and port start using my iCloud email address. Or maybe even go to Tutanota, which is free AND encrypted.