I remember hearing that IBM shipped computers with extra processors installed that could be activated if you paid the fee.

In searching for more information, I found https://www.ibm.com/support/knowledgecenter/POWER5/ipha2_p5/... which talks about activating and deactivating not only processors but extra storage.

It doesn't seem like that would work very well for most laptops and phones, given how people won't pay for online backup or anything above the minimums.

Anyway, IBM had a vision of "computing on demand" many years ago but it wasn't in the cloud, it was in your data center.