I don't think it was very difficult to forsee what we have seen with the market. I am probably talking out of my ass because I don't have access to really data bit:
1) BB user base declining which leads to less players on the market and a decrease in supply of players on the TL. However because of how BB is structured, demand in many aspects of the BB economy is exactly the same. In USA, we don't really have a DV anymore but we still have exactly the same numbers of DIII/DII/DI teams. Prices go up. Not surprising with demand constant and supply decreasing, prices have gone up.
2) You can make all the arguements you want about the percentage of players in free agency vs. rest of the TL, but limiting the supply of players has helped led to the drastic increase in prices.
3) Hoarding tax has created an incentive for people to spend their money or they lose it but with a decreasing pool of players it had lead to higher prices.
4) Increasing promotion bonus once again has increased the amount of money in market but with a decreasing player pool has helped increase player prices.
The only remedy is to increase the supply of players and/or find a way to take money out of econmy. Increasing the supply of players is easy. You get rid of FA limits which will help in the short term and you increase training speed which will help in the long term.