[jamescostian]

Many iOS users use the Messages app to send and receive text messages which can be trivially backed up to iCloud but not other cloud storage solutions. Among people who text (common in the US) I'd imagine there aren't many iPhone users with less than 5GB of data stored in iMessages

That said, you can back iMessages up to a computer and back up files on your computer. You just can't restore iMessages to different Apple devices like this, but now we're talking about minor grievances to a really tiny segment of the population