According to that article, as long as the crossover is correctly designed, even a 7 inch woofer can be easily integrated with a 1 inch tweeter. The article also fails to even mention the dramatic decrease in distortion/compression and increase in dynamics afforded by the larger woofer.
Anyone who has compared a 5 inch to even a 6 inch speaker can readily hear the differences in the overall size of the "sound." The article also spends a lot time talking about 3 and 4 inch woofers, which I never see anyone seriously tout as being superior to 5 inchers.
A nominal 6.5 inch woofer (frame width) will have a radiating diameter somewhere in the 5 - 5.5 inch range. That's an easy crossover point (~2.5kHz) for any competent tweeter nowadays.
5 inch woofers are great for those with limited space and budget. I have owned many and they can be quite good. A larger woofer (6-7 inches) can offer some very significant advantages in sound quality and *my only point* is that they shouldn't be immediately discounted as being inferior to <5 inch woofers.
I would be totally shocked if the (very, very tiny) increase in far off-axis dispersion would be able to be detected in a double-blind test.
Another thing to consider is that increased dispersion in the upper midrange around a typical crossover point isn't always desired in a highly reflective room. A more limited dispersion pattern can even be a benefit in those situations.
Again, I like and own many 5 inch bookshelves, but they are in no way superior, in every way, to their larger siblings. All things being equal (which they rarely are, of course), I'd wager that many people would prefer the larger presentation and increased dynamics (i.e. lower distortion and compression) of larger speakers even at moderate volumes in moderately-sized rooms with a sub.
That said, I can totally see unique situations where the extra midbass could be detrimental in very small rooms at very close distances. In those rare cases, a smaller bookshelf might indeed work much better. I also recognize that I have preferred smaller versions (Wharfedale 10.1 > 10.2 come to mind) of speakers from the same line, but it's certainly not because of their far off-axis dispersion pattern which is mostly inaudible IRL.
If I'm coming across as hating 5 inch monitors, I don't mean to, as they can offer tremendous value and versatility.