Best way to look at it is how it works without titanforging. Mythic raiding still gives the best gear in the game.
Once you realize that, then realize all gear has the same chance to upgrade.
So knowing that the chances of a heroic item titanforging to a mythic item level is tacked on.
So to get a 425 from mythic is much more likely than doing so from a heroic.
So on average, the statement is still true: the best gear in the game comes from the hardest content always.
However, it’s of course still possible, so now look at that possibility this way.
It WASN’T possible before. Meaning that difficulty was useless to you. Now it’s not. So you have more things to do in the game to increase your characters power level.
But you are upset about other people getting it?
No need to be. They are either your friends or associates and helping you killing things. Them having more gear is good for you.
If they aren’t, then you don’t need to be concerned with some one you don’t interact with. There are also people out there who win the Powerball, while you are working your 9 to 5. But no need to be upset about that because you don’t know them.
So, tldr. Gearing works the same way it always does at a base level. Do the hardest content and get the best gear from it. But if you really want, you can do other content and actually have a chance at getting player power, where you used to have no use for that content.
If some one else gets an item you want, don’t covet. Celebrate their luck if they are your friends, put it out of your mind if you don’t know them.
I think that is the healthiest way to look at this topic, whether you enjoy it or not.
Hope that helps.