What I'm saying is similar to the third quote, where you start after the abstract by reading the last 1-5 lines of the introduction. Only if you want to proceed

What I'm saying is similar to the third quote, where you start after the abstract by reading the last 1-5 lines of the introduction. Only if you want to proceed further do you dedicate the time to read or skim the entire intro, which can span multiple pages. You save tens of seconds and a lot of thinking this way, plus it helps frame things by giving a concise statement you can reference as you ask "how does what I'm reading build towards the paper's goals?"