What you are in fact talking about, are Google's death stars like the Shopping box, Knowledge Graph etc. It's fully understandable why many SEOs can't stand them 'cause whole categories of websites (price comparison platforms, for instance) have already fallen victim of such death stars, and there will be certainly numerous other portals, which will lose almost all of their traffic in the near future. Despite your (quite good) suggestions on how to circumvent such an issue, the situation for such an endangered portal can be hopeless when it's its whole business model, which a new Google feature makes obsolete. See geizhals.at for a very famous example.
All your content, social media, brand, and other online assets that you develop in that process are there to stay. And they keep going up in value as time goes by. Even if you stopped investing in organic search, these assets would still be working for your business. You’d get traffic because you’ve built an ecosystem that fuels itself. Now imagine that you’re generating traffic and you’re paying little to no money for it. Your cost per organic visitor will decrease by many factors as your return increases. Bear in mind that this is a cumulative effect that happens over time. Still, it’s a fantastic position to be in.
I think for agencies as far as how we appear in organic search ourselves, we are definitely going to need to leverage all 3 of the solutions you talk about and agencies who haven't branded their products/services are going to have to do that and are going to have to also employ branding strategies. In addition, we have to optimize for other search ares like you say in your point #2 and we must look at optimizing existing content for voice search and answers/featured snippets like you say in point #3.
Although it may have changed slightly since BrightEdge published its report last year, the data still seem to hold true. Organic is simply better for delivering relevant traffic. The only channel that performs better in some capacities is paid search ads, but that is only for conversions, not overall traffic delivery (Paid Search only accounted for 10 percent of overall total traffic).