Earlier quoted context omitted.
Let's consider a library with both a manned librarian and a self checkout, two different queues, same objective. Let's call the self checkout the 'highway' queue and the manned one the 'surface street' queue. Each of which could be expanded to improve throughput (more lanes:more self checkout lanes, more streets:more librarians). Ultimately the problem with anti-car rhetoric is that it seeks to limit access to the ob…
In your example, replacing bulky self-checkout machines (analogous to removing road/surface parking real estate) offers a significant benefit to everyone. More room for what everyone actually wants most: books. The preference for self-checkout machines forces a cost on everyone for the benefit of a few.
To the specific example, removing self checkout lanes makes sense if the removal adds more value than the lanes were providing, but not if they are providing more value than their opportunity cost -- perhaps because of woefully understaffed registers and a buggy mobile checkout app the self-checkout machines are responsible for a large portion of checkouts. Which would make them counter productive to remove.