>> The encrypted chunks of the file are stored, without any user-identifying information, using third-party storage services, such as S3 and Google Cloud Platform.
I completely agree with you, but your initial argument was that "Joe Infinity page ∞" wouldn't be indexed because Google cannot index every viable page on the internet. That is true, and Google will certainly set limits on what pages is crawls and what pages it indexes. However, in this instance the articles were crawled and they were indexed and they were relevant at one point in time. But google decided to remove them from SERPs for some reason or another (age, lack of traffic, etc).
That's really not relevant to this article. The author is not talking about crawling and indexing the entire web (although he mentions the "whole web" once, that's clearly not what he means). He is wondering why old pages -- pages that used to be in Google's index -- are no longer showing up in SERPs even when using appropriately-targeted long-tail queries.
Sure, but that's just more reason to use HTTPS across their entire domain and would help prevent users from being phished as easily. If I enter "apple.com" I expect all links on that page to point me to the correct location. A MITM attack from a non-HTTP page could easily alter the page and link me to https://www.xn--80ak6aa92e.com/login instead.
I do the same and it really helps my productivity. I have no clue why it actually works, but I've been using the strategy successfully for a few years now. I always suggest the idea to a coworker if they're stuck on a problem or find themselves unmotivated.