Maiden's legacy will have been cemented as a bloody brilliant live band in particular after the LOTB tour. And that's what Steve wants. If they end up releasing 17 or 18 studio albums it won't change their legacy.
Of course a new album will change their legacy.
They'd have had poorer legacy than they do now if they'd quit before TBOS, and an even poorer one than that if they'd quit before TFF and so forth.
In ten years time when there's no more tours and only the memories remain, the albums will still be there, and I'd have preferred there to be 18 or 19 (or more!) of them, and if that meant no second legs of Legacy of the Beast (and Maiden England) it would have been a deal I'd have gladly took.