Automation costs a lot. The projects I work on are almost always in the millions of dollars,band they're far from being considered "big" projects. The hardware manufacturers will sell you equipment that runs for thirty years. Companies are reluctant to replace working systems.
I replaced a PLC a couple years ago. The software to program it wouldn't run on my laptop because it used the win16 API. It used LL-984 ladder logic, and most people who were experts in that have retired. It's got new shiny IEC-compliant code now, and next they're looking at replacing the Windows 2000 machines they control it with. Once that's done, it'll run with little to no change until probably 2050.