I find it hard to see anyOne (excuse the terrible pun) having a need for 30 device license.
It would sort of require a family of 8, each with four devices, Windows, Android, Apple or Ios
That link offers an excellent price on both the 5 device and 30 device license which I'm sure
you would use for an extended family.
It isn't the price that I question, but 30 devices, that would need to be a fairly large extended family. Not everyone is using all 4 types of OS - Windows, Android, Apple or Ios - so that would mean even more in the extended family.
If these licenses have to be managed through one account the IT guy for that extended family has some work on
I mean looking at the forums for instances those who have purchased a license through Google Play have to deal with Google Play (and probably the Apple App store) for renewal etc. I don't know how they would get around that.
I simply can't see the need for a 30 device license.