I assume anyone using automated beautify features is not one of the people who prefers short lines.

I do accept the reason that white-space:pre might be in play.
Could there be a setting or tweak to assume that white-space:pre is not used?
Or, this might be a bit of work to implement, and I am not sure of the performance impact, but you could also check the rendered CSS for its presence. (Live CSS already shows this?)