I think there are a few things this thread ignores.
Yes, people from a "top 20" school might get a second glance at their resume, which might make it easier for them to land an interview.
No, it doesn't automatically mean that they'll get the job over someone else.
No school can guarantee you that you'll be viewed equally at every school you apply to.
Yes, some schools might make it easier to get published in certain journals.
Different countries have differing opinions on which schools are considered the best.
Schools rich in finances might be able to provide more resources.
Some schools are lowering cohort sizes by 1-2 spots in order to better provide resources for current students and to increase the percentage of students they place.
Advisers are important. Advisers can move from school to school which can impact placements.
Some advisers might have contacts at certain journals which might make it easier to get a piece looked at.
Not everyone wants to be placed in an R1 school. Some students would prefer teaching a 3-3, 4-4, or 5-5 rather than doing research. I don't think it's proper to say that one system is better than another.
Some schools are really good at "placing above their level" when it comes to fellowships. Sometimes, the connections from those fellowships are what allows them to move up the chain.
The majority of people on this forum will not land a tenure-track position no matter where they go.
There are schools currently outside the top 20 that have made dramatic changes in recent years which may or may not impact them. (Prior to these rankings, I think Chicago was previously ranked 10th? Indiana and UC Davis were not considered to be top 20 schools. And Michigan was outside the top 10.)
Rankings can change
According to the USNEWS:"
"Rankings of doctoral programs in the social sciences and humanities are based solely on the results of peer assessment surveys sent to academics in each discipline. Ipsos Public Affairs conducted the surveys in fall 2016. U.S. News conducted the survey of doctoral programs in criminology and criminal justice in fall 2017.
For the surveys conducted in fall 2016, Ipsos sent each school offering a doctoral program two surveys per discipline. Questionnaires were sent to department heads and directors of graduate studies in economics, English, history, political science, psychology and sociology – or, alternatively, a senior faculty member who teaches graduate students – at schools that had granted a total of five or more doctorates in each discipline during the five-year period from 2011 through 2015, as indicated by the National Center for Education Statistics' Completions survey. These rankings were published in 2017.
The questionnaires asked respondents to rate the academic quality of the programs at other institutions on a 5-point scale: outstanding (5), strong (4), good (3), adequate (2) or marginal (1). Individuals who were unfamiliar with a particular school's programs were asked to select "don't know."
Scores for each school were determined by computing a trimmed mean – eliminating the two highest and two lowest responses – of the ratings of all respondents who rated that school; average scores were then sorted in descending order.
These are the number of schools with doctoral programs surveyed in fall 2016: economics (138); English (155); history (151); political science (120); psychology (255); and sociology (118). And these were the response rates: economics (23 percent), English (14 percent), history (15 percent), political science (24 percent), psychology (14 percent) and sociology (33 percent)."
It is unlikely that every grad program is paying attention to every other grad program. Different schools excel at different areas. It's up to each individual to figure out whether a school can ultimately help them out in reaching a goal.
A student who excels at a "top 20" school does not necessarily mean they're more talented than someone who went to a school outside the top 20. It just means they were a better fit for that one school.
Some recent job postings have recently required applicants to have taught a certain amount of classes. Sometimes, that number isn't possible for someone whose only experience has been in a PHD program.
Some universities do better placing students at nearby universities or nearby states. Some students refuse to enter the national job market. Some people are open to the international job market. This number isn't the same at every university which further impacts numbers.
If you're purely interested in an R1 school, your chances increase if you go to top 10 school. However, there are no guarantees ever.
Find a school that appreciates what you can do and that can help you excel in. A degree is useless if you have to drop out because you don't feel supported and/or are suffering from depression. Depression is very real in grad school.
Not all top students go or are admitted into a top school. Some do manage to work their way up but the cards are stacked against them.
Be prepared to work hard no matter where you go. But don't be discouraged if you don't get into a top 10 or top 20 school. There are a number of schools in the top 50 who are doing some pretty cool things.
Also: Find a school that has a stipend you can live on. Don't be afraid to ask how students live. (How far do they live from the university? Do they live alone or with roommates? Is it by choice? Do they need an additional job to survive? Do they need to take out loans?) You won't be rich by going to grad school but you shouldn't have to worry about where your next meal is coming from.
Don't go into debt for a degree which has no guarantee of a job at the end.