Once upon a time, Thanksgiving was an over-the-river-and-through-the-woods-to-Grandmother’s-house-we-go kind of holiday. And for many of us it still is.But for a growing number of Americans — those who work for the growing number of retailers that ignore the national holiday instead of letting their employees observe it by staying home with their families — this Thursday will be just another day at the mall or the big-box store. Instead of the “day of Thanksgiving and Praise to our beneficent Father who dwelleth in the Heavens” that Abraham Lincoln proclaimed, a century ago, what they’ll be observing is business as usual.Part of the problem is that Thanksgiving comes late this year, cutting short the Christmas shopping season that’s so critical to the retail chains. These are the 27 days that will make the difference between red ink and black for 2013, so the now-traditional shopping frenzy of Black Friday is no longer enough; retailers also need Gray Thursday. At least they believe they do.And part of the problem is that retailers are nervous about the economy, not at all convinced that the recovery has really taken hold, and they’ve heard projections that the average Joe and Josephine will be spending 2 percent less this year than last.And part of the problem is that they’re afraid that shoppers are afraid of what Obamacare will bring, so they’ll spend even less than those projections project.And part of the problem is that retailing is like an arms race: If everybody would disarm, everybody would be safe and everybody would save a lot of money; if every store would close, no store would have an advantage. But nobody wants to take the first step, so everybody stays open. Or nearly everybody; a handful of chains are holding out, but who knows if they’ll hold out again next year.And part of the problem is that if bricks-and-mortar retailers were to close, even for one day, the etailers would be right there to take up the slack in the online marketplace.No matter which way you slice it, Turkey Day will mean lots of choices for shoppers, but hardly any for the workers who serve them.So maybe it all comes down to good old-fashioned greed after all.At least that’s traditional.