On the face of it they appear strange decisions, but we don't have the full data that is available to the executives do we?
From the point of view of a fan, I'm dissappointed, but I never felt that GW were in the rpg business for the profit margin anyway. It was more a way of promoting their brands through different media. Most games, as I have been informed by somebody who works in GW, only have a shelflife of about 3 years. If you consider that WFRP 2nd edition has been out since 2005 it kinda rings true. It appears that BI were going to do a similar 3-year plan with 40K, but something seems to have forced a strategic rethink from GW on this.
I think the decision smacks of the news of an impending recession in the UK - and the execs may be looking to consolidate their lines somewhat.
To be sure, the issue isn't whether the rpgs were profitable, it's whether they are as profitible as other potential investments (like novels). My feeling is that the costs of setting up an expensive rpg like Dark Heresy is significantly more than that of a new novel (or even several novels). Novels also don't suffer from a marketing limitation in the same way that rpgs do, where the learning curve and usual fanbase concerns about 'system preference' and so on, aren't a factor of selection.
I don't like the decision, but I suspect the businessmen are doing what is correct for their own interests (as usual). In terms of simply making money, the business execs are almost always proved correct.