I run a league that has been active for about 4 years now. Its mostly family. Every league I’ve ever been a part of, there are always 1-2 teams that give up and quit during the season. It sucks for the teams that lost early on to these teams but everyone after basically get a free win. Been trying to implement different things throughout the season to keep people interested. 12 teams $100 entry. $1000 of that gets split up between 1st ($600), 2nd ($300), and 3rd ($100) place and the remaining $200 goes towards weekly challenges, an elimination challenge and to worst/best record. It worked for the first few years but this year had 3 teams quit after about week 4-5, This year I only had two teams that did not win any money back. Its fun keeping up with all the weekly challenges every week but next year I’m thinking screw it, $1200 to first place. No other payouts at all. Winner take all. Maybe this will keep people more intersted than what I have been doing. Wanna hear what other leagues do to keep teams playing throughout the year? Or maybe its just inevitable, and nothing can be done about it. Thanks!
The tail does not wag the dog. If a team does not play kick them out.
Watch how quickly everyone falls in place. Just my view after playing many a money league and knowing better. 
We had 8/10 making playoffs for this reason, which is too many. Started as a work rec league fun but enough of us are into it pretty seriously that we keep upping it.
Honestly, people even try to win the loser games. They make friendly bets even.
Next year our commish came up with a pretty cool payout system.
—Team 9/10 are out of it…no money.
—1-4 make playoffs and play for two weeks/two weeks. 1v4, 2v3, then winners bracket.
—But teams 5-8 play a losers consolation bracket each week.
Essentially 5/10 teams are guaranteed to make their $100 back which should keep interest.
First place regular season: $50
- $400
- $200
- $150
- $100
- $100
Not set in stone but our plan tentatively.
Welcome abvoard!
Simple solution, assuming your platform allows you to do this. At the first sign of tanking, lock their roster and then don’t invite them back next season. If you have to, set their lineups for the rest of the season.
By the way, assuming this is redraft, also add random draft orders every year, so tanking carries no value to the losers.