Well, I agree to some extent. True, many people run a dual career job search as though they are running two single career job searches. I agree that, when one member of a couple applies for a position, they should also consider whether it is a good fit, overall, for their partner/spouse, at all levels. On the other hand, in many fields, there are so few open positions to which one can apply, that this sort of planning may not be possible - you apply to any place that has an opening in your discipline, and hope that they can take your spouse, as well.
And of course, when the two are in different fields, this sort of planning can become way more complex, even prohibitively so.
While perusing the job ads this week, I came across a few ads that straight-up targeted dual career couples in multiple fields. Instead of having one ad for each position, multiple schools within an hour or two drive of each other explained that they knew how difficult the search was, mentioned that it was entirely reasonable to live between the cities and commute both ways, and posted lists of what they wanted with links to the detailed individual ads to try to encourage people to apply together in a possible win-win-win for two schools and lucky couples.
I don't know how well that works in practice, especially with the multiple departments in multiple schools involved, but since I saw multiple ads of that type this year while never having seen any ads of that type in the past 6 years of looking, I thought it an interesting possible trend. Mr. Mer and I don't need that, but the numbers of people who do is only increasing.