At this point, I feel like the only thing that separates the 360's online infrastructure from their console competitors is their speed. Updates and download speeds are generally faster on the 360, while the download system on PS3 is often frequent and tedious. I have at assume that these faster speeds are in part possible because people are (sort of) paying into them. The MS server guys can continue validating needing faster speeds by saying "if we're as slow as PSN, people may consider whether our service really is more valuable."
The obvious counterpoint, is, of course, that you can take advantage of those speeds without paying at all, and it's ludicrous to think that MS would ever restrict their download speeds to favor Gold members (I mean, they could, but it'd be stupid). So Gold members are paying into a pool, of sorts, where faster download speeds and more consistent servers are paid by some people but benefit everyone. To keep this up, MS has to keep charging for Gold. Now that the competition (PS3, not necessarily Wii/U just yet) in terms of features, MS has a harder time justifying that $60, but they have to keep charging for it.
It's a weird corner to paint yourself into, but there they are. And in case anyone thinks I'm defending MS, I'm not. I think Gold is bullshit, and I only renewed last year because it was $30 and was tax-deductible (I reviewed a couple 360 games for money the year I bought it). My theory could be entirely off the mark (I'm not an expert), but that's why I think they're still charging for it. That said, I largely agree with the article.