I don't disagree that it is a bit of a spit in the face for people that did stick around and wait out the huge timer. All the same, methods change and improve over time. PotD solo was made possible from a basically impossible state with the addition of sustaining potions, and then became even more accessible when the Shadowbringers MCH rework came around. Does that devalue the efforts and work that people who cleared before Shadowbringers? Maybe a little bit, but that achievement still requires effort and skill to obtain. It didn't become free with the changes over time. Old ultimates also become easier as they age because of potency inflation and ilvl syncing quirks.

I personally don't think that being subbed and handing over a small stack of items once a week for 3 years is really something that you can devalue the efforts of by making a system that a good portion of the player base interacts with once an expansion or never at all be more accessible. There's also the fact that these achievements don't come with any rewards beyond the points like a title or a mount, so while people would definitely do so, there really aren't that many people that would care enough to do it. Botting and cheating are definitely a huge problem in game, but Leves is not a place where I would expect to see much, if at all, mostly because there would be no positive gil/item reward for doing it with option 2 or 3.