It never was about all that onpage stuff, it always was about the User <> Google <> Website triangle.
I by now sold a few thousand copies as Ebook and print. Mostly in the German spaeking markets. 5 Stars based on 22 reviews an the german Amazon.
Currently mostly doing other ventures so very very happy to give it away and make SEO agencies (and myself) redundant for good.
The point of most on/off page SEO things like meta tags and link building is to help Google understand what needs your website can satisfy.
If your content solves problems effectively, and Google understands how to connect you to the people who have those problems, that's when things work.
The priority is the advertiser. I think google has given up on indexing the web and just sends searches to authorities like wikipedia, let's face it thats what the "average user" wants, and best part is the rest of us have to pay to compete.
Pains me to say it, but is in the best interest of the searh engine to maximize the searcher's satisfaction.
Ultimately, someone comes to a search engine with a need. The search engine's top priority is to satisfy that need. That's the relationship that matters to the search engine. That's the customer. Supplying you visits is not what the search engine cares about. Your source site is a means. It's not the ends.
Your website page rank, and such are effectively irrelevant. The priority isn't you. It's the asker. They have the need. They need to be happiest.
Yes. Of course. There are things you can do help the search engine help others. The key to maximum effectiveness is to understand your role and your place in the process.