King of Wakanda Job Requirements...
First win the throne in trial by combat... Check!
Second hear the nations tribal issues and grievances... Check!
Third try and get an early bid on a potential queen... Check!
Fourth maintain the isolation status quo and protect Wakanda's interests... Check!
Exactly what kind of development were you expecting when the job requirements are mostly external in nature?
As a king you don't jump the gun on anything you wait for certain things to happen and come your way otherwise the job is not a job but a hobby!
Other super heroes can tinker with technology because Pepper Potts is holding it down back at the office... Even Superman does not suit up until Lois Lane is in trouble!
The close associates and incoming enemies set the table for the narrative otherwise you are a character picking fights just to try out new weaponry and super powers!
How is Queen Gorgo of Sparta any different than Nakia who encouraged the whole narrative for war or outreach to their kings?
Black Panther: "THIS-IS-WAKANDA!!!"
https://www.youtube.com/watch?v=4Prc1UfuokY