Come on man, if you have a pitching staff with four guys who win 15 plus games in 2023 you have the best pitching staff in all of baseball. By a large margin. That just isn't the way that the game works anymore.
As of right now Seattle leads the majors in staff era. They have three pitchers on the whole team with more than 8 wins, with one at 14 and one at 13. Toronto and Milwaukee are just behind Seattle. Toronto has four pitchers with more than 5 wins. One guy has 15 and the second best has 12. Milwaukee has one guy with 19, one guy with 16, and no one else more than 9. And their pitcher with the fourth highest win total is actually their closer, which seems rather bizarre. Next on the list is Tampa, who has one guy at 15, one at 12, one at 11, one at 9, and no one else over 5. After them is San Diego. They have a 14, 13 and 10, and then an 8 and a 7. And if you want to look at if from a different direction, Atlanta has the best record in all of baseball. They have an 18 a 14 and a 12, and no one else more than 8.
I have no idea when the last time a pitching staff had four starter at or even close to 15 wins each, but I'll bet it's been a long time.