People in /r/redditalternatives are talking about a "Reddit 2.0" What website would fill that role?

Exactly this. Looking at the top response it details it's hard due to a ton of costs like operating costs and hosting costs and stuff, but with federation these costs can be spread around so that it's more manageable for each individual instance (as content doesn't need to be viewed from the original instance but gets spread around).

The mass-scale casual interaction producing flashes of surprising relevance can't happen when the conditions aren't pulling in so many people that the 1 in 300 million person with the answer doesn't casually happen across the question that only he/she can answer. That's the unique content from Reddit.

Link aggregation, message boarding, messaging, all that stuff is merely tech that lots of other places have. Reddit's moat is the user presence which other platforms can't just replicate. Reddit needs to die first so that 1 in 300 person stops going there and goes to other places and somehow runs into the question there, hopefully in a way that they turn up in Google search.

Is the fediverse where that happens? Seriously asking because I'm no expert on it. It doesn't seem like the concept can scale distribution at that level. There will be pockets of interaction, but not everything is shared everywhere.

People just want easy. They dont like change, and they don't want to use their brains too much.

We can only hope Meta comes to rescue us /s