Re: Not unless you consider it a good use of the "big back end system"
"...and appropriately in such a way that it can be swapped out without the adjacent layers noticing if and when it becomes necessary."
I would not consider the sorts of applications that make use of esoteric IE6 functionality or rely on deprecated UI interfaces in the host OS as fulfilling that criterion either. I merely offered the sort of very simple, very-thin client, text-based interfaces that some businesses rely on and have done for many, many years as an example of making something that has a long operational life and that requires very little done to it, if anything, when the other end, the client bit, needs to change. Changing something in one place is, usually, far easier and cheaper than having to change it in ten thousand places. As many of these "web form" type applications are feeding information back to a central repository, having excessive complexity at both ends makes things much worse.