Most of the books are meant to be consumed in parts. This book explicitly mentions "Segue from previous chapter" for most chapters indicating what key concepts are continued in exploring/building new ones. Also, I believe any reader on HN can make sense quickly of the basic definitions needed to understand a concept in isolation.
However, mathematics is especially known to require continuous dedication for years to attain any sort of mastery.
It depends on how rigorous/detailed you want to be. This is at most two semesters worth of material, and has a very shallow learning curve (hence the large PDF). If you've been exposed to these ideas, you could cover it in a semester. I'd say it's quite doable in a year in your spare time.
If you drop the combinatorics chapter, it is definitely doable in one semester.
For example, Chapter 7 is 100 pages. In Tao's analysis book, he covers the same material in 42 pages.
It might, but it shouldn’t. There are 8 chapters and most of the content in the first 7 shows up in any run of the mill “Introduction to Higher Mathematics” or whatever that university decides to call their first actual math class, although occasionally combinatorics will replace number theory content.
> Everything you... wanted
Far from being "everything" anyone would want or need, it's rather "some (fundamental) things" you must know. A couple of pages a day, on average, would get you there within one year.
Kids, cherry-picking students of other disciplines, those who really understand what is a good read.