Of course, there is a lot more that needs to be considered but this is a simple example of how all of these things work together. I would recommend having no less than one page for each step of the organic marketing plan if you are a small business. The larger your business the more planning that you should do. If you do not think through all the details you will miss something that will cost you.
When a search engine user in the targeted area searches for the keywords or keyphrases that you chose, your ad enters an immediate online auction. Your ad is displayed when it matches bid and relevancy criteria, so you want to make sure that you have an appropriate budget size, and that you are bidding on keyphrases relevant to your products/services (such as those indicated on your website or landing page). You are not charged when your ad is displayed, but rather when someone clicks on your ad to take further action.

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.
Another one of the benefits of SEM is that people who see your PPC ads are those most likely to want to buy your product or service. PPC ads require you to choose a geographic location and specific search queries to target. As a result, you can be sure that anyone who clicks on your ad is not arbitrarily surfing the web, but rather, is looking for your product or service and in a position to do so.
By 2004, search engines had incorporated a wide range of undisclosed factors in their ranking algorithms to reduce the impact of link manipulation. In June 2007, The New York Times' Saul Hansell stated Google ranks sites using more than 200 different signals.[25] The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages. Some SEO practitioners have studied different approaches to search engine optimization, and have shared their personal opinions.[26] Patents related to search engines can provide information to better understand search engines.[27] In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users.[28]
Now, it is not that these sites are not interested in Google users. In fact, they have hired us to help them increase their share. However, they are getting so much traffic from sites like Facebook that it seems there is less urgency about attracting this traffic and less willingness to change the site to meet organic standards. Not long ago, sites would urgently and unquestioningly abide by Google’s standards to court that traffic.