once upon a time, promotion teams could very well win the NBBA title in their second season. (Upsyndrome, Golden Horde; Tucumcari took two seasons)
The salary floor hikes in s34 and s37 along with the loss of the cheap TL prices of the seasons 20s may have put a damper on this golden age of playing everything right to make a powerhouse team. Tanking still can happen, but it isn't near as effective as it used to be. I suspect my experience isn't unusual where by the time you get/train the right players and get that NBBA promotion those players are 1-3 seasons away from skill losses, you have no money left in the bank to adjust anything, and your players are worth half of what a younger replacement costs.
(Would like to point out I had to look up when those salary floor raises were. I'm nerdy for this game, but not that nerdy.)
(Would also like to point out that I would have likely promoted to NBBA in s32 except I had the fortune to match up against an ascendant Upsyndrome in the DII finals.)
(Have I mentioned I hate Upsyndrome?)