I don't speak for the management either, but my take on it is that it's hard to be any kind of an expert on "gadgets" in general, and individual SE sites like Apple and Android make more sense. The communities are very divergent - in some cases even hostile toward each other - and it doesn't seem to make a whole lot of sense to shove them all under one roof.
I know you could make the same argument for Macs vs. PCs on Super User or .NET vs. Java or PHP on Stack Overflow, but gadgets are not standardized like computers and programming; almost every question is sort of a niche question, you need to really focus the community to ensure that those get answered, and I think the somewhat dismal answer rate and relatively low question rate demonstrate that when it comes to gadgets, people would rather stick to their own little insular cliques than participate in something much bigger. Or, much more simply, they just don't have the breadth of experience necessary to fulfill such a role.
That's just my take on it, though. I haven't really actively followed the gadgets.se proposal/site (because I felt from day one that it would be too fragmented), so take this with several grains of salt.