If we observed Abraham and Lot in their day-to-day ( if you prefer, working) lives, we would not see much difference. They both had the same profession and obviously could do it just as well, as evidenced by the story of their separation, where it is explicitly stated that the flocks of both were large. Both were wealthy, both cared for their families, both enjoyed the dignity of their surroundings (Lot used to sit in the gate of Sodom, indicating his status as an elder of the community). They were both related, they were of the same "religion," so a superficial observer would not notice much difference, except perhaps one, namely that Lot resided in the city, while Abraham camped as a nomad in tents and did not settle in the cities.
For the sake of completeness, we might add that the two were certainly alike in that they had many human faults. But when we look at what drove their lives and their decisions, it becomes obvious how distant these two people really were. From the beginning, when God called him, Abraham made decisions toward heavenly things, even if it meant losing - security or standard of living. This accompanied his departure from Ur, but especially his stepping into Canaan from Haran. He builds altars in the Promised Land from the beginning because there he worships God, looks to heaven, and perhaps in part already understands God's purposes for it and his descendants. It is as if he views these things as paramount, and his prosperity and expansion as second. All this Lot witnessed for years, but we never read that he had the same motives. Lot was no more concerned with spiritual things than he was with earthly things. He also believes in the same god, but he seeks first and foremost his success on earth. He doesn't need to think too much, he knows what is important to him, as we saw in his breakup with Abram. I cover this in more detail in the June 2021 reflections - can be found in the tabs on the right.
Inner attunement leads each person unwaveringly down a particular path. Quite symbolically, it led Abraham to the heights, while it led Lot to the lowlands of Sodom. Abraham sought the things eternal and was given the gift and blessing of the temporal. But his life was not easy. Or else, had he chosen the lowlands, it would certainly have been easier. Lot, on the other hand, sought primarily temporal things, and wanted to find an easier way to them. That's why he chose the more fertile areas when he broke up with Abram.
We see Abraham as a man in two modes - as a capable businessman, a skilled trader, and on the other hand as a man of God. As he follows God, we see his inner spiritual growth and how he prioritizes this second side, which becomes his defining characteristic. Every man of God must go through the same process. Lot, on the other hand, functioned only in the human mode, even though he also believed in God. Yes, he was a man of quality. But he didn't get any further. Unfortunately, in the time of trial, that alone was not enough to save him.