The type rating is the big factor, and that's largely driven by desire and/or pressure from customers.
IMO type ratings, and particularly the categorization of types, needs an overhaul. The current type rating system is, IMO, the primary indirect factor leading to the max accidents (customers demanded the impossible - more efficient engines with a 37 type rating) as well as countless other design decisions that seem silly from the outside.
The P-8 having EICAS is more of an indictment of Boeing than anything (the P-8 is a Navy 737). It’s completely technologically possible, just that entrenched interests (namely, Southwest) kept Boeing from advancing the technology of their aircraft.
IMO type ratings, and particularly the categorization of types, needs an overhaul. The current type rating system is, IMO, the primary indirect factor leading to the max accidents (customers demanded the impossible - more efficient engines with a 37 type rating) as well as countless other design decisions that seem silly from the outside.