On the site Decathlon2000.ee, every statistic you can imagine for men's decathlon is archived.  (No women's multi-events, however - if anyone knows where they keep similar info, please e-mail me or use the forum.)  For each year after 1984, the complete records, including event results, of anyone scoring over 6800 points exists.  I noticed the list for 1985 was fairly long; 547.  However, only 372 from 2006!  Hoping this was not an indication of something serious, I plotted out the last 22 years of decathletes that scored over 6800 points, and discovered a very disturbing trend - a sharp decline in the number of athletes, plotted in the following chart:

This trend would be sad, but not dire for the sport, particularly if the quantity of those scoring over 7500 or even 8000 was going up (lower quantity of total athletes, but higher quality).  The trendline for the numbers of athletes scoring over 6800, 7500 and 8000 all point downwards, however.  Worse, they all converge at zero at almost the same exact time.  Statistical trends like this do not lie - unless there is a reversal, the decathlon will fade away, and fast.  The following chart shows that if the trend continues, in 60 years the clock will stop for the last decathlete:

So what's happening?  It's most likely a combination of many things, such as no sponsors, lack of high school and college support, MTV/X-Games/ADD.  Worse, these causes self-perpetuate, because less multi-event athletes today mean less coaches, administrators, supporters, fans, sponsors tomorrow.  Phil McMullen was tenth in the world in 2004 with an outrageous 8285 score, but was 4th in the US trials and missed the Olympics by a few points.  He "barely scrape[d] by."  How do you recruit athletes into a sport with this record?  Compounding matters, the physical ability of decathletes is staggering - but why stay in a sport where you're a world-class athlete but can't feed yourself, when the MLB/NFL/BOWLING/ANY SPORT HERE awaits with $300,000 league minimums?  Because you're totally insane (God, I love this sport!)

The Decathlon is never going to take over the major professional sports (or even bowling) in popularity, talent draw, or sponsorship.  But it's dying, and something needs to be done.  Never one to just state a problem and moan about it, I've listed some possible culprits, and some possible (but as always, difficult) solutions:

There are more, I am sure.  And many of these may not be realistic (or even wise) but it's starting things down the right path.  No sport should be quagmired too deeply in tradition to not welcome change and advancements.  Maybe the decathlon and heptathlon are just a few multi-million dollar sponsors away from a rebirth, maybe this is just a brief glitch in an otherwise healthy sport, and maybe a serious re-tooling of the multi-events is in order.  Whatever is going on, let's spread the word; e-mail or use the forum , get on the master's forums, start dialogues with high school and college administrators and coaches, and let's do something about this.