The issue with the rankings, afaict, is that they are the opinions of a relatively vocal minority who follow Maiden's music in a current basis and regularly exchange ideas and opinions on even Maiden's lesser known stuff. We have threads dedicated to the equipment each band uses, who wrote what songs when, links to books written by members of the Maiden crew who left said crew over 30 years ago. We are, for the most part, a very driven and informed community in regards to Maiden and we absolutely do not make up the majority of Maiden fans. I'd argue we're less than 1% of that total.
RTTH is a great song in and of itself, but in Maiden's extensive and prestigious catalog, I doubt it would be anywhere near the top 10 let alone top 50.