> it's a tension in the system
Yeah, of course there is "structural" slack (and tension) in any system, but don't forget that "Solidarity Forever" is only two things: 1) a default, initial reaction to managerial imposition, and 2) a chant leveraged to temporarily concentrate force towards the resolution of a crisis.
In meetings, and between workers, there's plenty of room for sober, reasoned planning and rational debate. So, it's NOT hard for a pro-union person to acknowledge systemic tensions; there's a time and a place for both tenors of rhetoric.
Furthermore, there are tensions in the un-unionized firm that also neglect the customer. Remember Deming's first theorem: "Nobody gives a hoot about profits." That's a commentary on managerial and executive tendencies to prioritize personal well-being, short-term gains, activity over productivity, and easily measurable metrics. These are Emperor's New Clothes of their own, frequently unassailable due to corporate culture.
Meanwhile, even saying the word solidarity can met with reprisals—let alone actually discussing unionization. So, I just don't think it's an model for your point given the current discursive hegemony.
Again, I agree with you that at times solidary furvor quashes rational dissent, but it's a deliberate, mechanical part of the union's anatomy and not a religion... mostly. And, secondly, it's silly to make an example of a union hegemony under our current anti-union climate. In fact, I would say, perpetuating this narrative of the mindless, frothing union berserker is harming working families' leverage in an age of increasing labor precarity.
> sometimes "doesn't care" is just a reflection of poor management
I might say, it's a reflection of poor compensation, but I guess that goes under the umbrella of "poor management". I suspect that the venn diagram between yours and mine definitions of "poor management" would have some surprising overlap... and otherwise.