Those statistics would be taken into account if they were to ever consider merging worlds again. As for the rest of your post, if I had a dollar for every time I've mentioned that the lack of advertising is the only reason the game is less active now than it was in 2010 I'd be able to fund an ad campaign myself.in my opinion, migration/merging worlds is a quick and painful fix that doesn't solve anything in the long run.
with this approach worlds can merge over and over again until we have only one world left. for the last few years Inno is just milking their existing customers without any serious attempts to attract new players. to keep this game running, they need to restore balance between old players leaving and new players joining, or even better, have a surplus of new incoming players. if you have two worlds that are played by 70% of the same people, you're not doing anything positive by merging them together.