I think a big problem is that corporate culture dictates that you're either growing or you're dying; there's no inbetween. Taking on debt to produce more product to service a market that might not be big enough to justify that debt doesn't seem to be an uncommon business philosophy. Harley fell victim to it in a major way, believing that their rapidly booming sales up to around 2006 were an indication that the whole world was dying to buy a Harley, in spite of their market research telling them that their target market was rapidly aging out of ownership, and they had no plans on how to penetrate into a younger demographic. Their response, as sales plummeted, was to try and turn the bike into an expensive boutique brand by limiting production while raising the price. Current sales figures for them pretty clearly point out that that idea isn't working. They seem surprised that motorcycle riders for some reason aren't willing to part with almost 50 grand for a Harley touring bike.
KTM also may have very well overestimated their future market for what is a fairly expensive motorcycle with a reputation for both high performance and maintenance headaches/quality control issues. There's a definite market for expensive motorcycles with sex appeal and a reputation for "character", but it's a finite market. I'm sure it's easy to look at the sales figures for a couple of good years and start believing the idea that everyone wants your bike, but quarterly sales figures and balance sheets can pretty quickly throw cold water on that fire.
Businesses and investors love unrestrained growth, but there's anotherr name for unrestrained growth: cancer.