I remember the Black Sabbath revival around 1997, but they had three things going for them that Maiden didn't at that time
1) Ozzy just came back to Sabbath and was becoming a reality / chat show star
2) the youthful 90s bands were wanking themselves silly with Sabbath worship (from Soundgarden to Pantera to even cooler bands)
3) Sabbath were by then 3 decades away from their origins and were definitely a legacy band in their 50s
By comparison, Maiden didn't have Bruce, weren't yet being worshipped openly by trendy metal/rock bands, and were only late 30s in their ages. I'd argue that Maiden have reaped the 'legacy band' respect that is rightly due to them around the same stage Sabbath were in the 1990s. Ten/fifteen years later of course, esp. when the 80s became cool and retro again.