Why not? Oil changes, belt changes, Valve adjustments, how are they any different? Sure the FI could go bad but then so could
It's not that simple.
If something goes wrong with a carb, an owner could get away just by maybe using a can of carb cleaner, and cleaning the carb.
A fuel injection system have several additional components - like a computer, an oxygen sensor, fuel injector(s), fuel pressure regulator, additional wiring, and an electric fuel pump. Any of these components can get faulty and even mechanics with many years of experience usually need expensive diagnostic tools to trace a problem.
In short - a carb is a lot easier and cheaper to service, than tracing and replacing a faulty part on a FI system.