The problem with getting players who are "Better than we have but not top 5 level" is that when we've gotten those players, they have had an extremely high failure rate for us, and everyone else. They've been the ones who have dropped off partially to a ton, leaving us hanging. They're the Samardzija, Frazier, LaRoche, Encarnacion guys. So in the back of our heads, we're saying "Yes Joc has had a 130 wRC+ against righties in his career and we need that...but a tiny dropoff in that platoon split and suddenly we've got another flop".
It's also...not wrong. Back when we were spending money, 2015-2017, I went through the guys you might consider "mid-level" free agents, the guys making $10-20 mil a year, and found that consistently the "bust rate" in them of guys where you want out of that contract was like 70%. It improved the last couple years as the FA market stalled, but in general those are just bad signings. You convince yourself the player has been consistent for x number of years and then you wind up having them take an immediate step backwards once they get to you, and it happens over and over. Your 2015 team signs 4 of them, Robertson performs well, but then you're asking how your other 3 big acquisitions all disappointed - those are normal numbers for these guys.
Sometimes you have to do that, if we have money to spend this offseason Joc makes sense, but gosh darnit it would be so nice to try out one of the kids in that spot.