True. However, brand recognition ads occur more in the consumer space than in technical market. Especially in a market of mostly small vendors, they're trying to sell, rather than establish a perception of the brand.
I'm not sure why DDJ should be limited to software tools vendors as its core of advertisers. There are hundreds of companies with solid budgets who want to get in front of developers in general to influence technology choices and purchase decisions - especially in the SaaS, platforms, infrastructure and cloud spaces.
I don't think the problem is yours, editorially, but being a little blunter than I like to be.. I wonder if the right company owns DDJ, because this is as much as a gold rush period as any other and DDJ remains in the upper echelons of its niche.
(Disclaimer: I sell advertising of this nature on developer related properties.)
