"You cannot have these modifications that you had in the on-premises world"
Well I guess the world is going to do without cloud.
It's incredible that one company thinks it can dictate to all its customers how they are supposed to conduct their business.
So, The Cloud is not only "give me all your data, you might be able to work with it most of the time", but now it is also "you work the way I decide you work".
Well, in a word, no. Companies have spent millions on tailoring SAP to their needs - when it worked - I doubt they're going to spend tens of millions tailoring their company to SAP.