Long Term Support is Long Term Problem
Having worked at a number of companies, I've seen the same pattern over and over with RH and RH-like systems: Long Term Support leads to unmaintainable systems. Same thing happens almost every time:
1) Project is installed
2) Patches are done regularly
3) People who set up the system leave the company
4) People keep using the old system as it was
5) Deadline for the end of LTS starts creeping up
6) Panic! We must update!
7) Realization sinks in that no one understands how the system works, no one dares touch it.
8) No updates are done
9) Hope you get a new job before it "matters"
10) Efforts to replace old system are nixed by management because, the old system is "working"
11) the old system keeps on running.
12) goto step 7
Now, I'm sure someone has a system that's been running on RH for 15 years, managed by several generations of staff and upgraded from RH5 to RH9 in a timely manner, using carefully written documentation. But it is rare.
I've seen all kinds of excuses as to why this won't happen THIS time, but ... go ahead, prove me wrong.
Let's not forget the case where the application requires newer versions of add-on packages (i.e., PHP) than the LTS distribution provides. That's a great way to reach step 7 before the LTS is up. The OS may be patched, but the application updates require a new version of something that's not in the distribution.
The only REAL way I see out of this trap is to do VERY regular OS and application updates -- at least yearly. Every time, someone new should do the update to test the documentation and shared knowledge, with the previous people on reserve in case something goes wrong. If you can't manage the update, you have the old one to live on while you figure out how to re-implement or replace the product.