It's not a binary choice. These 2 are the biggest GPU brands and so going long on both is a sensible idea since AI is here to stay.

AMD has a reputation for manufacruring CPU chips at lower price points with better performance vs Intel equivalents. Since Intel chips are invariably paired with Nvidia GPUs, I foresee AMD will be more competitive in the consumer market as it also produces better integrated GPUs that could give it a comparative advantage among budget-conscious consumers or those that use less intense AI applications. 

Conclusion: AI is the norm now so it actually doesn't matter if AMD has been slightly late to the game as Nvidia alone cannot produce enough chips to satisfy the market.