I'll address all your points as you broke them down:

1. Every company needs revenue. Social media platforms, which are free for users, require ad revenue.

2. You can implement the same stake weighted voting using some other resource as stake, such social capital - however you might attempt to define that.

3. Advertisers don't care about the content. They care about whether the content attracts eyeballs as well as whether the social media platform provides data that can allow them to most efficiently target potential consumers.

4. This goes back to my first point, which is that the blockchain isn't generating revenue, so how then can it be generating wealth? Additionally, as I mentioned in the OP, there is nothing technically stopping mainstream social media platforms from adopting this strategy of paying content producers and curators.

5. The only applications that utilize crypto currencies and are in some ways mainstream are those that allow you to link your bank account. The general consumer can't use crypto currencies to purchase everyday items. Its also too much of a hassle for the general consumer to go through various exchanges in order to cash out their rewards. In order for the platform to have the same utility in practice as in theory, users need to easily be able to turn crypto currency into cash.