To some people, Neil Peart was Rush and there is a quite fanatical (ahem) fan base, so I can see why it's happening.
There are other bands who've gone down that route though: Yes without Anderson and/or Squire, Deep Purple without Blackmore, The Who without Keith Moon, The Jam without Weller, etc.; they tread a thin line between being authentic and being a tribute with varying success.
I'm happy that the two remaining members want to play their songs and good luck to them.
However, I won't be going to the gigs: dynamic pricing is a rip-off and the O2 is a soulless venue; I want to actually see the musicians who are playing and if I have to watch them on a screen then I'll wait for the video so I can watch it at home.
I commented earlier about them cashing in and it's up to folks whether they want to pay; they've done it on some of their reissues as well, where the only way to get the hd Steven Wilson album remixes is to buy a £300 limited edition box set of each album; that's a no from me (and contrast with Yes doing the lot for around £50).
If they do new material and an album I'll probably buy it.