Here's a list of the lowest ranked 5-star player and the lowest-ranked 4-star player for a sampling of years. While the numbers bounce around a bit, there's a pretty clear trend. At the beginning of the list the "worst" guy who qualified for 5 stars was the 22nd or 23rd player. While the "worst" 4-star guy ranked around #100. In recent years the worst 5-star guy was down around #26 while the worst 4-star player was around #130.
Lowest 5* 4*
2004 - 22 99
2005 - 22 90
2006 - 23 111
2008 - 20 104
2010 - 22 112
2012 - 27 148
2013 - 23 115
2014 - 22 123
2015 - 25 130
2016 - 28 128
2017 - 24 130
Lowest 5* 4*
2004 - 22 99
2005 - 22 90
2006 - 23 111
2008 - 20 104
2010 - 22 112
2012 - 27 148
2013 - 23 115
2014 - 22 123
2015 - 25 130
2016 - 28 128
2017 - 24 130