essays can easily be fabricated or automatically generated

sure, i've done it, it's very easy to write one.

There is no guarantee of any kind that a person is a ceirtan way because he sent some text over the internet assuring anyone of those qualities

100% agreed

There is no way to trust any server unless it’s invite only where people only invite friends they know can be trusted

50% agreed. People's trust is easily gained sometimes and abusing this trust for invites is easy too sometimes. I first-hand saw a scammer become a rich guy's "right hand" and this scammer scammed the guy over the course of a year and then destroyed the guy's entire enterprise. Invites can be abused too.

If that’s how lemmy will end up then it will never be able to replace reddit

1. who the fuck thinks lemmy can "replace" reddit? that's absolutely retarded. Reddit is a multi-billion enterprise and easily the biggest content aggregator in the world. Lemmy has what, 15k people? A few genocide denial devs that are slowing adoption due to political people disliking it? A federated infrastructure build in people's smol virtual private servers and laptops in their garage running software? Lemmy may replace Reddit 5 years, but this tiny blackout will do jack shit against Reddit, it's just bad publicity that may delay their IPO for a few months until people forget.
2. The goal should be to take in as many people for now. As you say, the goal should be to broaden the net to get as many people. Expand servers, expand nets, welcome, and repeat, and then focus on other stuff. I don't see the goal as complete replacement of the network in the world stage but replacing it for those unsatisfied with reddit and that's very easy to do, just grab a shitton of people, give them a good place and that's it, they will make their own home there and if it's open source they will themselves make it better.

Having to interact with lunatics like you make me realize that lemmy is sure to die

it will not die. just as reddit will not die. it's growing, and it's federated, and it's open source. at the very worst case scenario, people will clone the repo, make their own shit like kbin.social and slowly move from instance to instance till they get some comfort zone. i don't think lemmy and its derivates will stop growing in the medium term just cuz reddit is giving free ads to alternatives by being shitheads.