Being an idiot is believing there has never been one Wakanda asshole who decided to spill the beans about the tech to the world. Ever. Or the neighbouring countries never noticing anything, ever. Or ignoring the fact colonialist countries would have tried to take over and make note of why they couldn't. A country being more advanced doesn't make them gods able to control the world, if SHIELD looked they would find out, Hydra too.
Atlantis comparison already been covered
Atlantis:
- A city
- At bottom of sea
- Nobody knows about it (is a myth at best)
- Doesn't interact with surface people.
Wakanda
- An entire country
- Landlocked between other nations
- Is known about
- Interacts with the world
- Draws attention to itself with its super metal.
See how one is more believably hidden?
Bonus, Wonder Woman!
- An island
- In middle of the ocean
- Nobody knows of it
- Cannot be seen
- Doesn't interact with outside world
Savage Land is stupid though. That shit woulda been discovered a million times already.
People have literally broken down all these points for you. There have been multiple posts discussing exactly why Wakanda is not some crazy unbelievable thing...and yet you're either dense enough not to get it or deliberately being obtuse.
Things that you were able to suspend your disbelief more for than a nation of African people who manage to keep their country mostly secret and cut off from the rest of the world (like, ya know, the real world parallels of North Korea or the Soviet Union at the start of the Cold War or Japan up until the Perry Expedition or various other real-life situations):
- A random US special ops soldier who exclusively uses a bow with superhuman accuracy to fight aliens rampaging through New York, superhumans, mutants and killer robots lifting a literal city 1000s of feet into the air despite not being superhuman in any way
- A mild-mannered physicist who turns into a creature of pure rage when he gets angry. Said creature will never let him die, likely can never die, has destroyed major portions of entire cities and can leap multiple miles at a time.
- SHIELD having carriers held up by giant turbine fans (lul)
- A scientist from the 1930s/40s developing a method of transferring his consciousness to a computer system based on vacuum tubes and fricking tapes
- Nazis creating superweapons based on glowing, magical, space-McGuffins
- A rich, super-smart industrialist who creates a suit of armor, complete with a power source of near-limitless power/capacity out of of scrap in a cave in Afghanistan where he was captured by some vaguely-but-not-really-but-possibly-Taliban-esque people. Good thing those dumb brown folks didn't at any point think to stop this dude from building his unstoppable suit of armor.
- Space gods who might be actual gods
- Fucking mermaids
- Fucking mutants on a city on the moon (a place we've landed, explored and thoroughly mapped even in this reality)
- A talking racoon
- A talking tree
Literally any of these situations/characters falls apart under the barest scrutiny with real logic. Now, you've tried to apply real logic in only the case of the Ultra Hidden African Nation as opposed to any of the equally ridiculous things and you're wondering why you're being called out on it.
HMMMMM, I WONDER WHY I'M BEING CALLED OUT ON THIS? WHY, WHAT COULD IT BE?