It's not impossible to make it, maybe based on something similar like Tor, but everyone would probably have to download everything, and I am not sure many people would do that.
I expect something similar to how Bitcoin is used: some people let Bitcoin Core download the full blockchain, but the majority uses light wallets that rely on a centralized server. Or multiple centralized servers, such as Electrum is using.
I wonder how many people would store all data knowing bounty report has relative big portion.
When a decentralized forum gets too big, we'll end up with centralized servers again.
And this happened to IRC. When it gets bigger, people attempt to mitigate it by only store/relay certain data. And AFAIK these days most people use IRC on Libera Chat server.