Here is what Udi claims:
If REST wants to conquer the enterprise, it had better get down from its "internet-scale" high-horse and start talking in terms of OLTP.This is like saying "if OLTP wants to conquer the enterprise, it had better get down from its RDBMS high-horse and start talking in terms of registries and bits and bytes."
There is always something that is at the lower level than the system under study. Just because there is a lower level, doesn't automatically mean we should stoop to it.
The entire point of the REST and the ROA is precisely the liberation from the need to stoop down to the lower level. Using these principles, one gains the necessary discipline to resist the ingrained challenge to stoop to the lower level.
In case this is not clear to you, keep in mind that REST stands for 'representational'. Representational means representing something that is at the lower level.
And since we have the representation to play with, we don't have to worry about the underlying lower level.
So, in this case, you can envision ROA being a representation of an OLTP system. Yes, we know that behind the ROA veneer there is an ugly OLTP system. But we don't want to really go there.
Just as we know that behind the OLTP system, there is an ugly flat file, assembler code system. And we equally don't want to go there.
So try and train yourself not to stoop to the lower level. Enjoy the privileges and the benefits of the freedom that ROA brings to the table.