Go through your rankings as well. Where it says where you are on the Global Leaderboard? (1736 for me) Click on that. There are LOTS of people not in Fellowships. Many of them will be inactive, so check them on Elvenstats. Or don't, just invite EVERYONE close to you on the global LB and hope a couple of them are active and want to join. But if you do check on Elvenstats, and their ranking has gone up this week, I find an invite and a kind Personal Message goes a long way.
Personally? Archmage is overrated. It's much, much easier to go to an established fellowship and climb your way to the top then it is to start with nothing and build yourself up as the Archmage. Just imagine the same thing with companies today. If you were a computer programmer, would it be easier to hire other people and build a new social media platform that becomes wildly successful? Or to join an already existing one like Facebook, and do so well you get promoted? Sure, there will be a few companies that become wildly successful. Snapchat refused to be bought by Facebook, now it's a multibillion dollar app. But lots of Fellowships/companies never take off. I've done both. (In the game, not a company) After 8 months, I got a 23 member Fellowship (after I merged with another). We got 4 chests in tournies and the first prize in FAs. I was dissatisfied, so I applied for the top Fellowship in my world in tournies, according to Elvenstats, even though I was still in my Fellowship. To my shock, she said I could come over within the day. Two months later, I'm Mage in that world. Mages have ALL the same permissions as Archmages, except disbanding the Fellowship and Mages can be demoted by other Mages. But if you're good, that's not a concern. Most Archmages are flexible, and if you want a change to the Fellowship, they'll probably make it if it's a good idea.
Again, Archmage is overrated, but it's entirely your choice. Game on.