In 2014, they played 11 ranked teams and featured a win over Duke in the Champions Classic and a stretch where they played 6 out of 7 ranked teams (they went 6-1). I think 2 of those losses came without Embiid who would've returned the next round making them a complicated team to seed.
In 2015, they played 15 ranked teams including a stretch of 5 out of 6 ranked teams where they went 5-1. Rankings are not RPI, they're determined by people with brains who watch a lot of college basketball. From the eye test, I'll be the first to say that I really didn't think this KU team was that good, but they still beat a lot of good teams.
13-14 was 11 ranked teams, but 8 of them in the conference. OOC, that Kansas team went 9-4, with one really solid win over Duke in early November. Kansas got a 2 seed that year based almost entirely on RPI and what it did in the Big 12- a conference that ended up getting 2 teams into the Sweet 16, and none further than that.
14-15, 12 of the ranked teams Kansas played were in the Big 12. OOC, they were 11-2, with 2 good wins, one over Mich State and one over Utah. Yet Kansas was seeded ahead of 29-5 Notre Dame, again because of RPI and the perceived strength of the Big 12, and again that did not play out in the tournament. 2 teams in the Sweet 16, none further.
This decade, only 4 teams have received a 2 seed with 8 losses, and only 1 with 9. And the results for those teams have not been very good. The 2 Kansas teams lost in the 2nd round, Duke and UL lost in the 2nd round this year. Only Michigan in 14 played up to its seed, losing in the Elite 8.
All 5 of those teams played in conferences that the RPI rated as exceptionally strong (that's the only way any team is ever going to get a 2 seed with 8 or more losses). Yet in 3 of those years, it didn't really play out. I mentioned what happened with the Big 12 in 14 and 15, but in more detail, the Big 12 in 14 had teams seeded 2, 3, 5, 6, 7, 9, 9. They finished the tournament with a record of 6-7. In 15, the seeds were 2, 3, 3, 3, 5, 9, 11. They went 5-7. Last year, the ACC received 1, 2, 2, 3, 5, 5, 8, 9, 11 seeds. Their final record was 11-8, which means 5-8 minus UNC.
The Big Ten in 14 is the exception, and showed well in the tournament.
I think the RPI is a mostly meaningless measure, and I think it has a tendency, for whatever reason, to bloat the Big 12's reputation. No doubt the Big 12 has generally shown well in Nov/Dec, but then the RPI locks into a cycle where, because the Big 12 might have 6-8 top 50 teams, it's almost impossible for any of them to drop much. Same thing happened with the ACC this year. As the dominant team in the Big 12 (to a ludicrous degree), Kansas has been a beneficiary of that phenomenon.
The SEC went through the same cycle in the early to mid 2000's, for whatever reason. Great RPI ratings, lots of high seedings, almost no results in the tournament.