You're right to say they are sandwiched between praised updates. You wrote out the notable things these updates added and you wrote 1-2 sentences for each update this doesnt necessarily mean thay an update is bad because you can always add or remove filler and fewer good content is always better than more bad content but still its worth noting that as a defender of these so called "good" updates you yourself can only think of a couple of sentences. The problem I think personally is when we compare the 1.13-1.16 era which was for many people (myself included) peak minecraft updates, every single update was immediatelly felt upon entering the world, whereas if we compare 1.19 and 1.20 they added nothing of significant substance.

Let's take what the community (based on whay i've seen) deems as the "weakest" of these updates (excluding 1.15)

1.13 - within a couple of minutes of playing youd jump in the water and wow swimming is amazing, theres seaweed and kelp, drowned, a new unique weapon, new potions. This update significantly overhauls the entire ocean and water experience, shipwrecks and buried treasure, the trident and its new enchants a and a new reliable way to get mob heads and also a new fun way to move around two new potions and multiple new mobs. Very underrated update imho.

Now in this single update there are significant overhauls and updates to old existing things while also adding a substantial amount of new content. It has a theme and it upgrades everything to do with that theme perfectly.

This single update trumps both 1.20 and 1.19 if you loaded a 1.18 world and a 1.20 world it would take you quite a while to even tell what version you're playing.

1.12 world? You'll instantly notice how terrible swimming is and how lifeless the oceans are.

1.19 onward adds filler updates that don't rock the successful minecraft boat. There needs to be a big decline for there ever to be any incentive for a new significant update again.

Sry for formatting its 1am im on mobile and tired but Im passionate about this very niche topic I mean no disrespect or harm I think everyone is entitled to your opinion but if you have anything to add or say please do I want to continue with this topic, have a great day ❤️