They won't because it has a far higher chance of backfiring. Plenty of people who play were invited by friends. I likely wouldn't be playing had a friend of mine not mentioned FFXIV and the roleplay aspect of Balmung. Yes, they could transfer to a smaller server with their friends, but if you've already established roots, are you really going to leave, especially knowing you cannot ever transfer that character? At this point, they have to wait for Stormblood to hopefully funnel people into less populated servers.