DKS reported disappointing earnings Monday night.  Its stock dropped by 23% in Tuesday trading.  So far this year it has lost 49% of its value, in a market that’s up by 10%.  …this in spite of the bankruptcies of rivals Sports Authority and Gander Mountain, which should arguably have cleared the way for better results.

The obvious culprit here is Amazon (AMZN).

I’m sure that AMZN is a factor.  On the other hand, although AMZN is growing at 4x the +5% rate of annual expansion of sporting goods sales in the US, the online giant represents only about 4% of the total sporting goods market.  DKS alone is 50% bigger–and its bricks-and-mortar competition has shrunk considerably.  So online can’t be the whole story.

I think two other general factors are involved:

–Millennials vs. Boomers, with DKS, to my mind, clearly oriented toward Baby Boomers’ tastes.  This issue here is that although Boomers have more money than Millennials, their star is waning as Millennials’ is rising.

–a “normal” business cycle.  During most time periods and in most parts of the world, in my experience, consumers are constrained in their buying by the limits of their income.  As new households form and families rent/buy a residence, rent/mortgage and, sooner or later, things like furniture become significant purchase categories.  This means less money for other purchases–like new golf clubs.

From the late 1990s through 2007, however, that wasn’t the case. Universal availability of home equity loans enabled consumers to avoid budgeting and prioritizing purchases.  So the typical pattern of contraction in some retail categories while housing-related, expands was absent for an extended period.

Now it’s back.  My sense is Wall Street has yet to catch on.

As an investor, I’m not particularly interested in the sporting goods category.  But I think the pattern I see here isn’t an isolated phenomenon.  If I’m correct, we should be doubly careful of any traditional retailer.