It's true that most of those would have lacked the resources to replicate AMD's feat with AMD64. OTOH, AMD itself had to buy out NexGen to produce their K6. Without AMD and/or AMD64, there'd be plenty of larger players who might decide to fill the void.
Without AMD, there was no alternative in the PC world, It was already the first 64 bit version of Windows XP.
Since we're providing suggestions in computing history, I assume you can follow the dates,
https://en.wikipedia.org/wiki/Windows_XP_editions#Windows_XP...