Well, the reason for all of that was that the flood of FAs ruined the transfer market because many of them sold "below" market value (read: the market value of similar skilled players went down because so many players of that skillset were on the market basically for free). Even with a bidding war, the pure number of players of those skills lead to low prizes.
Now that ever player of that skillset has a "price tag" of some sort - sometimes well above their true value (just take a look at those big guy players), the teams selling players don´t have to face such a huge and unrealistic figure of similar skilled players and have some kind of a shot of netting a "real value" for their players.
In addition, small and rookie teams gambling on FAs in the past often ended up with salary monsters for a non-investment.They tried to sell those players (which they rated a "bargain" impressed by their skills and their rating) for what they thought would be his real value, couldnt find a buyer and ended up in bankruptcy, while that monster became FA again. So the same players ended on the FA list over and over again, some of them ruining several newbie teams along the way.
Zwei Dinge sind unendlich, die Dummheit und das All...