How can Andre The Giant went undefeated for 15 years without ever winning World Title+7 other questions?

Please answer in kayfabe and real manner. Winning World Title is the goal of any WWE Superstars. Everybody wants to become a World Champion. Andre The Giant's the most dominant wrestler ever, he went undefeated for 15 years. But he went undefeated 15 years for nothing. He never won World Title. Instead, he... show more Please answer in kayfabe and real manner.

Winning World Title is the goal of any WWE Superstars. Everybody wants to become a World Champion. Andre The Giant's the most dominant wrestler ever, he went undefeated for 15 years. But he went undefeated 15 years for nothing. He never won World Title. Instead, he won World Title after he past his prime and that's only 45 seconds.

How can being 15 years undefeated doesn't earn him any shot at World Titles? And how can he's undefeated for 15 years but never facing the World Champion, the man on top of the mountain?

Other questions : (these 7 please answer in real manner)
1. When was Andre The Giant's prime years? From when to when?
2. What make Andre The Giant different from other giants? Other giant such as Big Show is also pretty agile, he can also do dropkick in his prime. So, what's make Andre special?
3. If Andre The Giant debuted in WWE now, would he still be portrayed as dominant as he was in his prime and 15 years undefeated streak?
4. If Andre The Giant debuted in WWE now, will he still end up as one of WWE's greatest Legend like The Undertaker? Or will he be just a Legend like Big Show?
5. If Andre The Giant debuted in WWE now, how many times World Champion he would be?
6. Can you name any wrestler from any promotion since 1990s who's more dominant than a prime Andre The Giant? If there isn't one, who is the most dominant after a prime Andre The Giant?
7. Do you think a prime Andre The Giant could beat a prime The Undertaker at Wrestlemania for The Streak?
Update: BQ : 8. Why do Vince McMahon finally give Andre The Giant one World Title reign the lasted for 45 seconds after Andre has been an old washed up has been??? Why won't he just let Andre The Giant retire as the best wrestler to never win World Title, instead of giving that crap 45 seconds reign
Update 2: Note : So, please have 2 answers on my question. Real means why WWE decides to book like that, Kayfabe means why do that thing happen in kayfabe (so we pretend WWE isn't scripted). For other 7 questions, please only answer in real manner.
Update 3: Note: I can't believe everyone doesn't pay attention to my note. Please give 2 answers : real and kayfabe manner. So, you have to explain why WWE decides Andre went undefeated for 15 years without ever winning World Title and in kayfabe how come he never granted a shot after undefeated for years?
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