The NYTimes is actually an example that undermines the ideals of RSS for the average web surfer who is not a tech geek.
The NYTimes RSS feeds are not full texts of the article such that a one can read the entire story within the comfort of the RSS reader. NYTimes only provides snippets and excerpts to bait people to click on to the real web page. For many normal people, this crippled functionality of article summaries in RSS is worthless to them.
Yes, many low-traffic WordPress sites still give RSS feeds of full text but that's not going to reverse the decline of RSS.
Again, I emphasize and concede that many hardcore web surfers (e.g. HN users in this thread) still find the limited RSS summaries useful because they don't have to "visit 100 websites" but that's not a problem the mass population has[0]. This "go-to-our-real-website-to-see-the-entire-article" amplifies the trend of RSS declining in popularity. If RSS is just "teasers", the typical web surfers would rather get their "aggregation" from Facebook or just use the NYTimes smartphone app which has enhanced rich content such as video, etc.
The publishers of popular mainstream websites simply don't have any economic incentive (i.e. ads) to give readers the full text in their RSS feeds.
I still contend that a bunch of RSS enthusiasts in this thread talking about how they use RSS doesn't answer actual the question the HN poster asked. The actual question is about mainstream trends and not about the habits of HN hardcore users. Take another look at the words used in the Ask HN question. HN users don't need to "hope" for a new web or smartphone RSS client. They're already using RSS right now!
[0] similar example previous comment from 9 years ago that makes a distinction between "normal mainstream" web surfers and hardcore RSS enthusiasts: https://news.ycombinator.com/item?id=2060707