It depends on the audience. Random boosters worked well for as long as the skirmish game lasted. I'll assume that the skirmish game's numbers started to wane before 4E, and the attempt to revitalize it at that point was just too late. I believe that is because they didn't support it like they did and do support Magic.Why are there still people saying "the random model doesn't work"? The random model worked just fine. In fact it worked brilliantly and obviously made Wizards a ton of cash for 7+ years, or however long the line lasted. Rising costs, a saturated market, and simple product fatigue killed DDM, nothing more and nothing less.
Those of us who played just the RPG (and I'll be making a generalization here, because I know I'm not alone) mostly stayed away from DDM because of the randomness. We have needs for (relatively) large numbers of similar types of miniatures. We might need four or five each of three types of goblins, or some similar situation. The purpose behind the collection was completely different than those who played the game. We weren't looking for minis to add up to a point total in order to be competitive; we were looking for minis to put on the mat to help create a story. In other words, we wanted to tailor the minis to our games--not tailor our games to our minis.
Unfortunately, Wizards didn't really take the shift in need into account when they stopped the skirmish game and just made minis for the RPG.
I fully agree with this statement. I think the economy is a major factor as well, and it has been for a long time now.The way to resurrect the line is simply to let it lie for a few years.
Once the economy recovers, and people have more disposable income, then I think WotC will try to revive their miniatures line. But when they do that, they need to be prepared to show the love, or people will just get bored with it again.