Speaking of irrelevances : to think of what might have been had they had even a modicum of pride in their legacy
As it is/seems to be: cash grab and late years ego boost. Might as well have Ariana Kardashian or BeyonZ as guests while they're at it.
What makes you think they lack pride in their legacy?
I don't think they need or crave a cash or ego boost at this stage. From their description of the reasons for the tour I think they just genuinely feel like doing it, urged partly on by a youngster who probably wants to feel part of his dad's legacy, doing what he does very well (I gather). When you've existed as part of that sort of creative unit for so long it can be hard to completely cut yourself off from it despite, or maybe because, of long gaps.
Who knows, there's still time for Ariana or Bey, or Jarry Beiber/Hustin Styles, to be signed up as guests. Yay!