It's a LOT different on Odin than it is on Fenrir it seems.
Because there are no GoV exp parties anymore.
And ever since Trust hit, from 1-75 had been 99.999% solo.
At least on Odin.

It's actually the other way around from my experiences:
1-75 solo
99 party randomly like before Trust.
(I don't abyburn because I don't want to have to spend months ungimping my lv30 stats at 99.)

So your argument of "well it's this way for me" just doesn't really hold water.
Now, if you then support your argument with "this is what I see on SERVER" then you have some credence...
And on Odin, there are no GoV parties anymore. You're more likely to find a Valkrum Dune exp party.
On Odin it's Trust-solo until whenever you want to go to abyssea.
There's actually not a whole lot of "sorry I'm using Trusts" on Odin at 99... Cause the Trusts kinda suck compared to real people... So I see a lot more of people dumping Trusts to party at 99... And I see a lot more "no rather solo" at <99.

Maybe it's different on Fenrir, but partying before 99 is dead on Odin.

And I've never argued that this makes FFXI a solo oriented game....
But it DOES make it a MORE solo oriented game.
(Do people just no comprehend the meaning or comparatives? Jesus Christ... More =/= absolute)
If Trusts worked like Fellows, then everything would be normal.
But with the Trust function demanding solo play to be used, that gives incentive to play solo, thus making the game's experience MORE solo-oriented.

Making Trusts solo only was fine until the bugs for partying were worked out... But to always have it that way is just stupid.
Making them partyable allows for a person to play solo if they wish, and for random people to party together and not lose anything.
In other words: everyone benefits from such a change 100%.