I believe that the issue was more tragic than that (no expert)...

They wanted to 'hide' the fly by wire (FBW) as for it to be apparent would require that the plane (effectively) be re-classified as a new plane, requiring expensive up-skilling of the pilots. The existence of the new FBW was even hidden from the manual!

The FBW required information from the pitot tubes in order for it to know how fast the plane was flying. Planes have two such tubes, one for backup as they are prone to blockage. Normal practice would be to poll both tubes, and if their reading disagreed the pilot would be notified and assume blockage in one of the tubes.

However, they could not do this as a pitot tube warning would reveal the existence of the FBW to the pilot, who would not have been aware of its existence. Hence they relied on one pitot tube input and (of course) no warning lights.

This must have been a calculated risk on their behalf. They must have known that sooner or later it would fail.