The ideal situation is never having to upgrade: you buy your computer, install the operating system, and it works the same until you retire it. If your computer has a 5 year warranty, you expect to use it for at least 5 years before retiring it.
A 5 year LTS is only 5 years if you install the moment it's released, but that's not usually the case; for instance, there's a new Ubuntu LTS release every 2 years, so in the worst case your LTS installation will last only 3 years. Now consider the "10 year" RHEL LTS: in the worst case (you installed RHEL 7 just before RHEL 8 was released), your LTS installation will last 5 years, perfectly matching the warranty period.
If you want to know more I wrote about it in another comment: https://news.ycombinator.com/item?id=25348914
Most of those hosting customers are not tech companies building fractionally "innovative" CRUD SaaS apps. They're SMEs who use their apps and databases to do real work: organizing their employees, procurement, running payroll, managing delivery routes, order and stock management — boring stuff like that. They very much do not want to have to significantly rewrite the back-office systems their businesses rely on because the OS changed under them. They want it to keep working for decades with as little redevelopment as possible.
I really don't get this fascination with 10 year LTS. Why is it so hard to upgrade in half a decade ? I mean this is such an arbitrary number. If RHEL started offering 50 year support, people will complain that Debian is 1/10th of RHEL.