Not sure why you call it economics of scarcity. The distributors want control over the distribution method to make sure they are paid for whatever they are distributing, not to create scarcity. If something is popular, won't distributors try and sell as much of it as is possible.
The two are one and the same--the only way to force people to pay for something is to make that thing scarce. In the case of information, which is not naturally scarce, that scarcity has to be entirely artificial.
If something wasn't scarce--e.g. information sans copyright--then anybody could get it without paying. This is a practical reality that copyright attempts to change by legal means; the argument is that the legal means impose a larger cost than benefit on society.
The distributors wish to control the scarcity of the copies of content. If there is an overflowing abundance of copies then their model of enforcing a 1:1 sale for every copy breaks down.
