Nicko just called. Apparently, he wants a word with you…
I don't intend to disrespect Nicko in any way, but he was replaceable.
That being said, I really doubt that Steve would accept replacing/losing ANOTHER musician in such a short period of time. It'd go against the band's image. And also against Maiden's modus operandi. In contrary to other legacy acts from their era, Maiden always seemed to be a few guys who like each other and actually like working together. The reunion lineup was very stable for decades. Years ago (I think during the AMOLAD era), Steve even said that the band wouldn't continue without any of the musicians. We all know how it went, but parting ways with another musician of the current lineup just wouldn't look good.
I can't really imagine Maiden without Dave. He's been here from the beginning (the 1st record, of course - no one gives a damn about what was happening before that), the band's always been his priority. Hell, he's the one who starts playing Iron Maiden at the concert.
Also, would it be worth it? With only 1, perhaps 2 tours more? They don't have anything left to prove. Sure, in theory they still can continue playing good shows and releasing music, but we're talking about very few years of what may be. Nicko left before RFYL. This tour had to happen, it was almost mandatory. 50 years of artistic activity is a huge achievement, very few metal bands can say that they've been making and playing music for such a long time. It is a milestone that surely deserves an appropriate celebration. But after that? I don't see any big thing that could top it.
Of course, I wish all the best to the band and its fans. I hope we won't see anyone leaving the band. Just sharing my thoughts here.