Nice article. This topic has had a lot of threads in the past.
My take on it is, since the Beatles probably, people get very swept up in a mystique of "The Band." They imagine a creative unit of bonded souls for all eternity. The romantic image bears little resemblance to reality. All a "band" is, is a group of people who happen to be playing together at any particular moment. It's not a marriage or a blood brotherhood. Musicians come and go and play in different combinations.
Each situation is different. In a group like Yes, there was ALWAYS revolving-door membership. What matters more than which members are there, in my opinion, is continuity - I would say there's a difference between a situation where the group has been playing continuously for years, with some members leaving and new ones joining, vs. a situation where a group went moribund and then fifteen years later one guy hires all new people and wants to tour under the name of a group he used to be in. For groups like Rush or U2, on the other hand, it's been the same three or four guys together for forty years or more. You can't trade out any of them and still have it be Rush - the group identity is too much invested in the three of them.
The thing I'm glad the article points out is that band names are generally trademarks, and trademarks are property that can be owned, bought and sold. Same as Ray Kroc can manipulate contracts and take over the fast food chain, cutting the MacDonald brothers out of their own restaurant - it's not pretty and it's often not right, but it should caution us against piling too much importance on a name.
Oh, and I wouldn't call it a "reunion" tour unless you have a significant proportion of past members actually, y'know... reuniting.