Over and over, so much middleware software is abandoned due to the high level of customization and expense to replace it. Everyone knows old databases still being kept around, a spaghetti mix of highly configured software packages/vendors nobody wants to touch or pay to get replaced.

And the high expense of contractors to customize and migrate, keeps the legacy tech debt around.

But that is also what keeps an entire industry making money, and many legacy mom/pop shops employed for decades.