It's of no surprise that bots and now even ai powered ones are on the internet. I think OP misunderstands the problem. It's not so much that bots/ai/synth will outnumber. Quantity is unimportant because 1 bot with thousands of accounts is able to manipulate and change what's being discussed. It's that it makes you think there's human activity when there is not. 1 bot has the power to censor online speech on some platforms. Which is how you end up with the dead internet because real people whose speech is censored wont keep trying to talk about it on that platform.
A platform that's declining, will hesitate to ban bots or may even have their own synthetic engagement to justify that it 'looks like' they are still as popular as ever even though people have moved on.
Having experienced the internet on forums, then social medias, then this nearly entirely synthetic era. It's very clear we are living in the dead internet era.