My head hurts...
It would be awesome if you could just like stop. Please?
It is called "Undersized Party". That is the intent to that mode.
I'm going to repeat myself, please say it with me, "Undersized Party".
Ok, good? Sigh
It's intent was to allow smaller groups to attemp to clear older content for people who missed it.
It is not "Game made EZ". It is also not "Faceroll to Victory".
You also stated "has no value". If it has no value whatsoever, why is anyone doing it? The answer is simple, it does have value. It may not have the value it once did, but it still has value nonetheless. Those are things such as a title, a minion, Wondrous Tails, glamour, crafting items, orchestrion scrolls, gear for level 50 jobs. There are many things to value. Just because they aren't level 60 endgame things does not mean they are without value.
Since you followed my premise, I'll follow yours.
Oh, you didn't? Not shocked, but I will work with what you stated anyway.
At the release of 5.0, all 4.x content becomes face roll easy from that mode since mechanics and effort are hard. Basically all the content becomes a piñata, you smack it around a little bit with your "gimme loot" button and loot comes flying out of it all of the place. So much loot you are still picking it up a week later.
If that is the intent, why bother to play 4.0 at all? Seriously. If I can complete everything from 4.0 in an hour and get all the rewards in a day or two, why spend 2 years doing the same thing??? The answer is that beyond friends and a desire for what would now become artificially challenging content, there isn't one.
To go a step further, what if everyone or most people came to this same conclusion and cancelled their subscription for an entire expansion as there was no longer any reason to learn anything while it was relevant? I'm fairly certain the answer would be, death of the game as we know it. The loss of revenue would cause them to drop the funding of the game due to lack of revenue generated.
That is at least partly why it is not gimme loot mode. I agree that old content should get easier over time. I disagree that it should go from a challenge to "rolling for loot while watching Netflix" just because an expansion happened.