The reason they stopped is because the competition in the DSLR arena is really tough, particularly when you have Canon and to a certain extent, Nikon who are dominating the sales. I believe Canon are the only manufacturer who predict remaining profitable
throughout 2009, while Nikon is predicting some loss
in the later half of this fiscal year. Pentax, Sony and Olympus have been bleeding money and are unlikely to be profitable this fiscal year.
While all camera brands have passionate user bases, sometimes the financial and economic reality is hard to avoid. This would be terrible for consumers if the DSLR market had only 1 or 2 major players in it.