Lukasz' chart seems to be just his generalized, overall sonic ranking, and Lukasz, more than most, appreciates the nuanced sonic differences, and in his defense, if you dig around the Lampi Poland site there are other charts and descriptors that get more into the details. Also, keep in mind, I don't think WBF members are necessarily representative of the majority of persons in the audio buyer world. I think there are many audio enthusiasts that don't join audio fora and get into the weeds and roll tubes like we do, so, I think for those persons, the chart could be helpful.
FWIW, the chart aligns with my findings from Lampi's I've owned (Golden Atlantic, B7, GG2, GG3 with 11-P, and Pac2).
Anyway, I've never subscribed to "newer is always better" and I personally appreciate it when a manufacturer doesn't simply (dishonestly) create new models just to generate more sales, telling you last year's model now sucks and this new one blows the old one out of the water. If you watch interviews with Lukasz, he isn't ditching DHT because he thinks pentodes or triodes are superior- not at all. He still loves his DHT models. Also, some that have owned Pac and upgraded to Horizon, never heard their Pac with E11-P, or more recently discovered tubes, like PT14, Telefunken C3G, etc., used with TP adapters. For me, some of these more recently discovered tubes are very much component-level sonic upgrades. The changes are not subtle.
Me, I'm a DHT fan for life, but, I'll always keep an open mind. I don't think Poseidon would be an upgrade for me, not when I've maxed out my Pac2 with just the right tubes, but, I'm guessing from comments from an audio friend group, some of whom owned maxed out Pac2 and now own Horizon, Horizon would certainly be an upgrade.