I think the real irony is that much of the time fences exist because of the quirks (fences) of some other system you are stuck with. Sometimes it feels like it is fences all the way down. Other times, you work your way down 5 layers of dependencies and discover that the whole pile of ugliness is because the core system is designed around physically mailing boxes full of reel-to-reel tapes. When that is the case, there is potential for a cascade of "lean modern apps" to de-cruft an industry.