hmmm. Suprising that teams are packing it in this early in your league. This is our 5th or 6th year as a keeper league (previous 8 years were non-keeper). We have guys who pack it in, but usually not until June or july. As commish, i have no problems with teams building for the next season. But I would be worried if our owners were doing it this early too.
We have always had 7 keepers. We only allow 3 FA pickups for the season, but we draft 23 man active rosters and a 14 player farm team. So each roster consists of 37 players to start the season. This allows for every team to stash prospects for keepers.
Is yours a "prize" league? In our league the top four teams (out of 13) win something. It helps keep more teams interested in competing longer.
Our salary setup is odd. We do not do an auction. Most of us are older fellas, with families and whatnot and many of the owners did no want to spend the time to do an auction. (as it is, our drafts run 7 hours long!). However, we do have salaries for our players. Each team has $315 salary cap before the draft. The salary cap only goes towards your 7 keepers and 16 players you draft for your starting roster. We use MLB.com's mixed league salaries as our bible. Every year MLB.com posts values for every player. I have David Wright. His MLB.com value was $26... so I pay him $26. So, going in, you know what players are going to cost.
We have two year contracts for our players. Cole Hamels was $1 last season on MLB.com. I kept him at $1 for this season. If I want to keep him next year, I will have to upgrade his contract to MLB.com's 2008 bible value.
The guys we draft for our farm team don't count against the cap. But their MLB.com values count for next year if they are one of our 7 keepers. I drafted John Maine in the first round of the farm draft. His value was $4 (I think). If I want to keep him next year I get him for $4. After that, I have to go to bible value if I want to keep him again.
After keepers are declared, we have a regular draft where you know the salaries of every MLB player going in.
It took us a few years to calibrate the salary cap. But, as odd as it sounds, it works really well and there is still a lot of strategy involved.
Not sure if our league setup helps you at all. Just putting it out there.
Also, a few years ago I created a league history. Sounds a bit silly, but our league has been around for 14 years and I still had most of the records from all those years. In the history, I list each team and where they have finished each season and then I average out their place in the standings. It really adds to the bragging rights, as guys want to finish as high as they can every year so their average doesn't go down. Every year I re-tabulate the averages and hand out printouts to every league member on draft day. just another little added feature to keep guys competing longer.
Finally, it is all about the makeup of your league owners. I've known many of the guys in our league since high school (I'm 38 now). We are all ultra competetive, so guys fight to stay in it a little longer.
Not sure if anything I typed here helped. Sorry so long. Good luck.