He didn't say that, and it was 640k at the time.

It’s usually ‘640kb ought to be enough for anybody’

Which probably wasn’t actually from Bill Gates

https://www.computerworld.com/article/2534312/the--640k--quo...

I think that's a misinterpretation of the quote, Gates didn't say "More than 64kb of Ram may never be possible" he simply argued against its practicality at the time.