"Tanking" has been a big topic this off-season. First I think we should establish what we're talking about with tanking. The term comes from the NBA, but as far as sports go I only pay attention to baseball. This isn't because I don't like other sports, rather I'm scared of what would become of my life if I allowed myself to care about other sports as much as I care about Baseball.
However, it seems that in the NBA, "tanking" mostly just refers to gaining high draft picks. One high first round pick can turn around an NBA franchise much quicker than an MLB one. The draft is certainly a big part of taking in the MLB, but it's only half the story. Trade all your notable MLB talent and not only will you lose a bunch and get a high draft selection, but the team will also gain a lot of other team's former draft picks in the process. From my NBA-ignorant perspective, this doesn't seem to be as much of a factor in professional basketball.
A big part of the that is there is currently two teams extremely well positioned for the future after using the strategy for several years. From 2011 to 2013, the Astros lost 106, 107, and 111 games. 2014 was a little better as they only lost 90 games. The fruits of those purposely lost seasons arrived at the major league level in 2014 and 2015, and paid off in the form of a 86 win season, a wild card, and a team set up to contend for the playoffs for the considerable future.
Cardinals fans are a lot more familiar with the Cubs and their tanking. From 2011 to 2013 the Cubs weren't quite as bad as the Astros, losing 91, 101, and 96 games over that time frame. The Cubs are a good example of the MLB-specific tanking. The Cubs used those high draft picks to their advantage by drafting now-MLB talents in Kris Bryant and Kyle Schwarber, as well as close to MLB ready Albert Almora.
But on their way to tanking, the Cubs got just as many good pieces by trading away any MLB talent they had during the time. The Cubs picked up their franchise cornerstone first basemen Anthony Rizzo while he was still in the minors in exchange for starting pitcher Andrew Cashner. They got their shortstop of the future in Addison Russell in exchange for just a year and a half of starting pitcher Jeff Samardzija.
And just as it became apparent that these two teams would be strong for at least the next few years, the Braves went fully into a rebuild. The Phillies, constantly criticized for not rebuilding sooner, have also jumped into tanking. And now the league is starting to talk about this strategy. The Reds and the Brewers are getting into the fun as well, based not just on the sorry state of their on-field product, but the extreme competition in their division between the Cards, Pirates, and Cubs.
So there may be as many as four teams not trying to win this year, and all of them are in the National league. But, I'd argue that these teams should have started rebuilding sooner. I'd also argue that these teams probably just felt more comfortable with the idea of tanking after the Astros and Cubs did it. In that sense, the MLB is just a copycat league and these teams saw the benefit of tanking more clearly after seeing the new state of those teams. In that sense there was a backlog of teams that should have been rebuilding but weren't, and now we're seeing that backlog emptied in a single year.
It's pretty clear that the league itself doesn't want its teams to tank. Ideally, the goal for the league is for every team to have a shot at making the playoffs. That was the point of adding the second Wild Card. It keeps more teams' fans interested in the long 162 game season when they can imagine some scenario where their team can compete.
But at the same time, its obvious that the teams, at times, have seen an incentive to tank. It means lower gate receipts and TV ratings in the short-term, but the hope of several years of competitive years in the future that make up for it. Now that other teams have seen an extreme tanking strategy work in both Chicago and Houston, teams will only see the incentive more clearly.
But tanking certainly isn't the only strategy for rebuilding a team. The Cardinals' are a model of success for turning around an organization's long-term prospects without sacrificing the short-term. Sure, the Cardinals had losing seasons in 2008 and 2009, but the Cardinals' worst record in the 2000's (78 wins in 2007) bested any Astros or Cubs record between 2011 and 2014. Nevertheless, the Cardinals assembled one of the game's best prospect systems in the 2012-2013 off-season, and have won three consecutive division titles based largely on the fruits of that system.
MLB seems likely to do something, but do they really need to? It's unrealistic to expect every team to be competitive every year, and most fans aren't exactly content with their team being below average year after year. The Cardinals tried to stay competitive during down years not out of some moral disagreement with tanking, but because they didn't want their fans to completely tune out. Other teams did a similar analysis, and came to a different conclusion. Astros and Cubs fans had a few years of watching (or not watching) a very bad product on the field, but now those fans have every reason to be VERY interested in the team. It seems like a good trade-off for both the team and the fans.
If MLB wants to do something about tanking though, I won't shed a tear. The current rules don't allow for a consistently good team like the Cardinals to ever have a chance at the premiere draft talent. They largely have to get by by being one the best teams in the game at picking in the back of the draft. I'm not going to lie, anything that makes it more likely for the Cardinals to acquire a Chris Correa-like talent, I can at least imagine being on board with.
But there might be unintended consequences to whatever the league does. The current system is based on the premise that it helps competitive balance. A lot of teams are rebuilding right now, because their on-field product is already awful. It makes more sense to do that then to spend tons of resources just to push their way up to .500, like the Padres and White Sox did last year, and the Diamondbacks are doing this year.
So, what can the league do about tanking? I don't think the league should really do anything. It's never plan A for any franchise to spend several years not being competitive. It's a very costly decision in the short term. Generally, we're only seeing teams that are weak at the Major League level and in the minors, and for those teams there's not much else they can do.