MI CURIOSIDAD

Your guess is as good as mine. My speculation is that Hori changed his endgame plans three times. At first Hori planned on killing Endeavor early during the high-end battle.

 "Truthfully, Endeavor was supposed to die during the 6th season, but when I was drawing the High-End battle in Kyushu, I decided to delay that. Maybe because of that impact, there was a little delay after the High-End battle..."

At this point you can tell that Hori didn't think of how keeping Endeavor alive would effect the endgame plot, because Endeavor's arc remains stagnant since the Pro-Hero arc. He basically doesn't do anything, but is kept alive on the promise that he will eventually do something to atone. My guess is Hori simply didn't plan far ahead enough to think the point he wanted Endeavor's arc to end at.

In the original scenario me and class1akids speculated together that since Enji wasn't going to be there, Shoto using Phosphor would actually work to take down Dabi non-lethally and the confrontation would end there.

The second change is because Hori kept Endeavor alive, he needed to make it so Enji and Dabi had a final confrontation, but because he also made the choice to have Enji fight AFO instead, the battle had to be split into two parts with the finale being Enji and Dabi's confrontation.

This second change is what resulted in the horrific burning off of Dabi's skin. If not for this change then likely we would have got an ending where Shoto visits Dabi either in prison or in rehabilitation like Rei, and that's the first step to Dabi's recovery paralleling the end of the Tournament Arc.

The third time is that it's clearly foreshadowed that Toya would eventually be able to sit down at the dinner table, and Shoto would ask him his favorite food. Enji has a dream about his family eating dinner together and wants Toya to be there too, Natsuo once mentions he doesn't know Shoto's favorite food, much much later this prompts Shoto to think about Toya's food and declare he'll make him sit down and eat Udon.

What we got instead was Dabi in an iron coffin on life support, with his family just expressing their condolences and getting to say their goodbyes in the short time Dabi has left.

I have no idea why this change was made. Maybe to pander to a part of the fandom that loved Enji's redemption arc, but despised Dabi because of all of the trouble he caused his family. Either way it's very weird, because it's not just killing each character off. It's subjecting them to these ironic hells like it's the twilight zone. Toga wanted to know if the heroes would save her or they'd kill her like twice, the answer is no and they'd just put her in prison so she kills herself. Shigaraki was afraid that he was born evil and wasn't in control of his life, AFO reveals to him that apparently AFO controlled his entire life from the beginning, and then Deku kills him and he dies having destroyed nothing meaning his life was indeed meaningless. Dabi's greatest fear was that he was a born failure, his life meant nothing, his death was unmourned and his family moved on without him. Well, now Dabi is going to die in a life support machine with no skin that looks like the torture devices from hellraiser, slowly, painfully, only able to be conscious a few minutes a day and his family is just going to move on without him.