I don't know, although whether rugby union or rugby league has a higher profile depends on where you live and (whisper it quietly) whether you are working class or middle class.
But the public profile thing doesn't really work when you look at yachting does it - piles of knights but hardly what one would call a high profile sport.
But overall in terms of coverage in the UK Union is more prominent and the class difference is dependent also on location. Looking at the list, perhaps the combination of the team sport and the lack of achievement at international level has had an impact. Other than the mistake of not giving Bobby Moore a peerage, no British footballer has arguably had the type of success at the highest level that would deserve it. As for Rugby Union, a majority of the Sirs are New Zealand, indeed over many of the honours there are a comparatively high number of New Zealanders (the only one in equestrianism). This carries over into cricket with a good number of the Sirs being from Commonwealth countries.