As I suspected, I'm in the minority, but at least I'm not alone. I'll make sure to keep my subversive ideas to myself when trying to get published
Surely both approaches are viable. Much 'classic' sf was entirely plot-driven (or idea-driven, or setting-driven). It is often remarked that Philip K. Dick's characters seem interchangeable; characterisation is not what he's remembered for.
If one looks at the history of science fiction, its early templates - Verne and Wells, say - were adventure stories, albeit augmented in Wells's case with philosophical/social speculation. Adventures and ideas have continued to be central to its make-up. This isn't to say that characters were irrelevant, but those characters were usually the active, dynamic kind who would want to go on said adventures.
In contrast, what now tends to be referred to as 'literary fiction', descending in a line from, say, Henry James and Flaubert, is much more concerned with the introspective ruminations and stream of consciousness of individual characters. In literary fiction, you can get away with a story in which 'nothing happens' in an external sense - it could be a single character sitting in a room, reflecting on past miseries (and it very often is - heh). The average sf reader (the kind who mainly or even only reads sf) will not have much of a stomach for this.
What has happened in the last few decades (since the New Wave) is that sf has learned a few lessons from the literary mainstream, and there is now often more of an emphasis on character psychology and background than previously.* However, the most 'literary' of sf (e.g. M. John Harrison) will still sell far fewer copies than the latest space marine blast-athon. So I would agree with your initial post that, when it comes to popularity at least, character is
not the most important factor in sf.
* This may also have something to do with the 'bigger is better' publishing trend towards bloated books. Until the 1980s, most sf novels were in the 150-250 page range, whereas now 600+ page monsters are common, allowing for expansion - some would say dilution - of every aspect of the story. (We can argue about the pros and cons of this - I am generally of the opinion that it's a bad thing, leading in too many cases to literary redundancy and padding.)