What does "this" mean?

----The part of speech by former Steve Jobs , C.E.O. of Apple

I learned about serif and san serif typefaces,
about varying the amount of space between different letter combinations, about what makes great typography great.

 It was beautiful, historical, artistically subtle in a way that science can't capture, and I found it fascinating. 
None of this had even a hope of any practical application in my life. But ten years later, when we were designing the first Macintosh computer, it all came back to me.

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Q. None means "Not one or not any" , so  "don't exist", right?
What does  "this" mean?

Q2. Grammatically, Shoud  "this " be changed "these" ?
Because "None" should be used more than three ones in quantity whereas "Neither " is used in two option.
This is for the usage of "None" and "Neither"

Q3. Correct me  for my better English writing If you see my questions