It is a bit mystifying as to why Sandy Alderson is taking so long to do what he and everyone else — owners, coaching staff, players and fans around the Mets — know he has to do: get Ike Davis out of here and into the rarefied air of Las Vegas, where he can hopefully clear his head and rediscover his batting stroke. Maybe it’s because the Mets’ GM hasn’t yet decided what to do about the other half of the equation, which would be, whom to replace Davis with? The easy thing, of course, would be to simply move Justin Turner over to first base on a full-time basis. But right now, with the way this Mets team is playing itself right out of a season by Memorial Day weekend, Alderson has to do more than just send Davis out. While it’s true Davis’ funk has enveloped the whole clubhouse, and the rest of the Met players have grown weary of being asked “what’s up with Ike?” questions, there are plenty of other reasons for what ails this team, most notably the overall defeatist malaise seeping in, along with a sense of entitlement with some players. You can see it with each successive loss, six straight at home, 13 out of the last 17, all in which they’ve failed to score more than four runs, seemingly waiting around to get beat, resigned to the fact they’re just not going to be able to score enough runs. I’m not sure, at this point, if the defeatism complex settling in with the Mets can be eradicated. But, if nothing else, for the fans’ sake, Alderson needs to do something drastic to try to right things, as best as they can be righted, at Citi Field and demonstrate that he’s not just biding his time until next year. I’m not talking about firing the manager, either. Heaven knows, Terry Collins has done everything he can to keep this team playing, juggling his lineup around the currently useless Davis, continually trying to instill confidence in his struggling and delicate starting pitchers behind Matt Harvey, all the while wearing his increasingly raw emotions on his sleeve. It’s certainly not Collins’ fault that Davis has the second-lowest batting average in baseball, or that Ruben Tejada is hitting .211, or that three of his starting pitchers have ERAs of 5.00 or higher — any more than it’s Don Mattingly’s fault in L.A. that Matt Kemp is batting .270 with only two home runs and that his two shortstops replacing the injured Hanley Ramirez are hitting under .200.