We know that performance-enhancing drug (PED) use was widespread in MLB during the so-called "Steroid Era" when the owners, the players and most members of the media largely ignored the fact that players were bulking up, setting records, winning championships and stealing millions of dollars in salary as a result of boosting their production with the help of illegal drugs. We are supposed to believe that the "Steroid Era" is over because now MLB conducts drug tests and has a three-tiered scale of punishment for offenders: 50 game suspension for strike one, 100 game suspension for strike two and a lifetime ban for strike three; all suspensions are served without pay. Despite the institution of the testing program and the aforementioned penalties, 2011 NL MVP Ryan Braun failed a drug test (he was later cleared on a procedural technicality, with no scientific explanation offered for how his test could possibly been wrong) and Manny Ramirez--one of the top sluggers of the "Steroid Era"--retired in disgrace in 2011 after his second failed drug test (Ramirez later successfully lobbied to get his 100 game suspension reduced to 50 games and after serving that suspension earlier this season he is trying to make a comeback). Melky Cabrera, the current NL batting average leader (.346, .062 points above his career average), has just been suspended for 50 games; the only good thing that can be said about Cabrera is that he did not use the "dog ate my homework" type of excuse offered up by most cheaters who have been caught: he admitted that he intentionally took a banned substance.
What possible motivation could MLB players have to risk missing so many games and losing such a significant portion of their salaries? These are the two most likely reasons that MLB players could be caught using PEDs now:
1) The players believe that they can beat the system; perhaps many players are still using PEDs and getting away with it while only a few players are stupid enough and/or unlucky enough to get caught.
2) PEDs provide such a huge advantage that the potential rewards (money, stats, championships) outweigh the risks of getting caught.
Some economists insist that PEDs do not in fact enhance performance; I would not ask a medical doctor for economic advice, so I am not sure why anyone would ask an economist for advice about medical matters/sports performance but both the clinical and anecdotal evidence strongly suggest that PEDs do exactly what their name suggests: help an athlete to enhance his performance. Yes, that athlete still has to train hard but that is the point: all elite athletes train hard but the ones who take PEDs are able to train even harder and get more results from that training. PED usage can help a marginal prospect make it to the big leagues and it can help a talented player like Barry Bonds or Mark McGwire put up superhuman numbers. Cabrera hit .255 for Atlanta in 2010, .305 for Kansas City in 2011 and this season he not only set a new career-high in batting average but he made the All-Star team for the first time and he won the All-Star Game MVP (clinching home field advantage for the National League in the 2012 World Series). Cabrera made $3,100,000 in 2010 but after his poor performance that season his pay was slashed to only $1,250,000 in 2011. His increased numbers in 2011 helped him land a $6,000,000 contract for 2012. He recently reportedly turned down a three year, $27 million contract extension because he expected to receive much more than that as a free agent after the 2012 season.
It is not difficult to figure out the calculations being made by Cabrera and other MLB players; increased performance is literally worth tens of millions of dollars. Only the players know how easy or difficult it is to evade detection for PED use but if Ramirez and Cabrera (and almost certainly Braun, technicality aside) were willing to risk getting caught it is not much of a stretch to assume that either (a) a lot of other players are still getting away with PED use or (b) those are the three stupidest guys in the sport.
If drug testing works--and if PEDs don't work anyway, as some economists suggest--then why are players still taking PEDs? It is premature to assume that the "Steroid Era" is over; the drugs of choice may have changed and the methods for evading detection may have improved but the positive drug tests that we know about probably just represent the tip of the iceberg.