Second thing, optimizing across additional platforms. So we've looked and YouTube and Google Images account for about half of the overall volume that goes to Google web search. So between these two platforms, you've got a significant amount of additional traffic that you can optimize for. Images has actually gotten less aggressive. Right now they've taken away the "view image directly" link so that more people are visiting websites via Google Images. YouTube, obviously, this is a great place to build brand affinity, to build awareness, to create demand, this kind of demand generation to get your content in front of people. So these two are great platforms for that.

Novelty wears off. Even if people aren’t getting sick of your ads, your product itself will become less revolutionary over time. When Casper launched, a direct-to-customer mattress-in-a-box company was a hot new take on the traditional sleep industry. Now there are so many competitors that the idea of a mattress showing up at your door in a box just isn’t as exciting.
Search engine optimization (SEO) is the process of affecting the online visibility of a website or a web page in a web search engine's unpaid results—often referred to as "natural", "organic", or "earned" results. In general, the earlier (or higher ranked on the search results page), and more frequently a website appears in the search results list, the more visitors it will receive from the search engine's users; these visitors can then be converted into customers.[1] SEO may target different kinds of search, including image search, video search, academic search,[2] news search, and industry-specific vertical search engines. SEO differs from local search engine optimization in that the latter is focused on optimizing a business' online presence so that its web pages will be displayed by search engines when a user enters a local search for its products or services. The former instead is more focused on national or international searches.
One of the reasons for a traffic drop can also be due to your site losing links. You may be seeing a direct loss of that referral traffic, but there could also be indirect effects. When your site loses inbound links, it tells Google that your site isn't as authoritative anymore, which leads to lower search rankings that in turn lead to traffic drops (because fewer people are finding your site if it's not ranked as highly and more).
Paid search advertising has not been without controversy and the issue of how search engines present advertising on their search result pages has been the target of a series of studies and reports[23][24][25] by Consumer Reports WebWatch. The Federal Trade Commission (FTC) also issued a letter[26] in 2002 about the importance of disclosure of paid advertising on search engines, in response to a complaint from Commercial Alert, a consumer advocacy group with ties to Ralph Nader.

Search engine marketing (SEM) is a form of Internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages (SERPs) primarily through paid advertising.[1] SEM may incorporate search engine optimization (SEO), which adjusts or rewrites website content and site architecture to achieve a higher ranking in search engine results pages to enhance pay per click (PPC) listings.[2]
So just how much of the traffic that finds itself labeled as direct is actually organic? Groupon conducted an experiment to try to find out, according to Search Engine Land. They de-indexed their site for the better part of a day and looked at direct and organic traffic, by hour and by browser, to pages with long URLs, knowing that pages with shorter URLs actually do get a large amount of direct traffic, as they can be typed quickly and easily into a browser. The results showed a 50% drop in direct traffic, clearly demonstrating how all of these other factors come into play during the analytics process.
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 for a very famous example.
For instance, before launching a new product or service, a business can create a simple landing page to gather feedback from the target audience. Or it can run a survey asking a bunch of targeted questions. Or it can even go a step further and create a minimum viable product to see how the target users are interacting with it. With a bit of creativity, PPC ads can help gather real-time feedback that can be used to improve the end product, or idea.

The Featured Snippet section appearing inside the first page of Google is an incredibly important section to have your content placed within. I did a study of over 5,000 keywords where ranked on page 1 and there was a Featured Snippet being displayed. What I found was that when was ranking in the Featured Snippet, the average click-through rate to the website increased by over 114%.

At our agency, we work with sites of varying sizes, from very large to quite small, and recently, we have noticed a trend at the enterprise level. These sites aren’t relying as much on Google for traffic any more. Not only are they not relying on Google traffic, but also, the sites are getting less than 10 percent (or slightly more) of their organic traffic from the search giant.