If only there was some kind of a protocol, widely supported, that would allow publishers to push content to their readers directly. Readers could "subscribe" to (say) "channels", which would get populated with items published by publishers.
It could be a really simple method of sindication! I even saw a nice icon that I think would work well for it:
I think that's taking it too far and jumping to conclusions. I cannot think of a single instance of an instance admin inflating their numbers with bot accounts or in any other artificial way, and I've been on fedi before it was called fedi.
This is almost certainly external bad actors taking advantage of captcha-less open signups.