Dojji, what it comes down to is the the closer position is unpredictable all unto itself. There is a reason why there are teams who keep getting elite production even though they have high position turnover (Oakland, Tampa) from the closer role. The reason why paying for relief pitching is stupid is because teams who can identify talent have proven time and time again that you can play musical chairs with the position and still get comfortably above average/elite results.
It is failthought, because there are best practices established by other teams that absolutely dispel the need to spend big on a closer, or relief pitching for that matter.