Since my response is to the moderators of the site and Groundspeak et al., I will post this here weeks after the main discussion has passed. Like all of my logs, this is mostly just a rant.
I... support the decision! The sport/game/hobby of geocaching has existed for so long, its long term survival outweighs what some users think about the more antiquated elements of it. I would argue benchmarking is not a priority for many users, only partially because Groundspeak has relegated it to obscurity on the website for years.
Beginners, who are important customers to expand the product, don't seem to be flocking toward benchmarks. My area has been dominated by loop-holers focused more on statistics than unique hunts and only seem to log benchmarks when they can get a challenge cache out of it. The 0.13% statistic that was paraded around is probably an understatement, but I do not see the logic of paying to support something so little of the general population cares about. A majority of my gripes are not with Groundspeak's decision but the rotten system of global capitalism and the myth of unlimited business growth. Low interest, sadly, equals low profitability and thus elimination.
The archivist aspect is the main element that is tragic in all this, for me. But this is a symptom of the internet at large- huge portions of the web are just being lost to the wind and almost no one seems to care. Geocaching has now outlasted web 1.0, 2.0 and if the impending demise of twitter is any indication, 3.0 as well. One of its most valuable elements then are the logs from a pre-cell phone age. There are inactive users who commented on benchmarks and their logs will be lost forever. That sucks. While scraping page by page through The Internet Archive is a great idea, it's not practical. I'll try anyway. It's not a defense of the decision, but reality.
Burying the lede here, but Benchmarking is/was one my favorite elements of Geocaching. I think it is profoundly interesting from a historical aspect, and many of my most memorable experiences with caching overall have been hunting remote benchmarks. I was annoyed with how old the datasheet was and just how many of the marks were actually destroyed. Especially living in an urban area, where mindless sprawl and that myth of unlimited growth have destroyed many of these disks. But the ones I did find were fun, even if it was impossible to combine that experience into any sort of phone application.
Of the 84 I found so far, 56 (66%) have been radio/water towers, cupolas, domes, flagpoles, or just tall buildings. These are a majority of the benchmarks I've noticed other users have logged. Which is logical- they are the most easily accessible. But I would also argue, not entirely worth it. For those above me who complain about lamp post hides, these categories of benchmarking are very much in the same vein. I do not want to gatekeep against either as that would be hypocritical. I strive to give my logs as much depth and information as possible, but it's pretty obvious that a State Capitol dome is "in good shape".
Which leaves the other 32 (34%) of my finds- bench mark discs themselves. This is what I'll- and others here- will truly miss. I think that the amount of marks logged as missing or never logged at all are vast. That sort of eliminates the ease of accessibility. Of those 32 disks, a third of them have been found less than five times. I am the most recent finder on all of those for the past eighteen months. I was happy to recognize one of those other finders in these comments, and empathize with their disappointment, but this doesn't eliminate benchmarking. It just pushes it to a much less popular website. This is by no means the end of my benchmarking. It's just the end of me keeping track of my benchmarking online- my disapointments with Waymarking are a separate rant entirely.
Talk all you want about how the best things in life are worth the challenge, but from a business model perspective it's not marketable. Which goes back to my hatred of the "game" (capitalism) not the "player" (Groundspeak) trying to promote and protect Geocaching.
So in summary, while I love benchmarking, I can understand why Groundspeak would phase it out. Because it's a niche, mostly unrelated element to geocaching at large.