Agree that potting-up a badly rootbound plant, especially a woody entity, so often ends in failure of the plant. A totally different activity than a repotting that includes removing the old soil, trimming the roots, and using all new soil, whether a plant is placed into a new pot or back into the same one.
Trouble can also come from the way water is applied to loose, new soil, regardless of its' type. A gush or stream of water can instantly compact soil. A slow, gentle sprinkle can prevent that from happening. If done the first few times, the roots & soil particles should have become less susceptible to compacting. Maintaining the fluffy, airy texture of the soil this way has also made a huge difference in my results, much more so than using any particular kind of soil vs. another.
Starting with a peaty "potting soil" is something I would never do anymore because it is not a battle I want to have. I don't ever wonder how dry the soil is (except in a couple pots that have no drain holes,) how much water I should add, or whether it's too soon or too late to add more water, I just water all of the pots every 2-3 days during the heat of summer, every 1-2 weeks over winter. It's so much easier to just make sure that an uncompacted, naturally more airy soil never dries completely.
Not everyone cares for their plants in the same way, and the environmental conditions in which potted plants are kept cover a wild & wide range. If others also suffer from "looks thirsty" syndrome, their experience would have a good chance of being similar to mine. It's very exciting to me to just see healthy plants instead of struggling ones. If someone is occasionally losing a plant because they forgot to water, or drying more quickly than their schedule will allow time for watering plants, putting a plant in a significantly larger pot could be a great improvement.
In this article, Peter H. Raven, director of the Missouri Botanical Garden, offers a wonderful quote. https://www.nytimes.com/2007/0...
"Dr. Raven emphasizes that they are a radically different form of organism than are animals. Plants and animals have evolved along separate paths for hundreds of millions of years, ever since single cells began pooling their talents into multicelled beings. "Plants have evolved their multicellularity completely separately from animals, and any direct comparisons between the groups are wrong," Dr. Raven said. "It's as if plants evolved on Mars, and animals here."
In addition to their caloric self-sufficiency, plants can be envied for their eternal youthfulness. A plant elongates itself through constant cell growth in two zones of its body, at the very tips of the roots, which grow down into soil or other surface to which the plant clings, and the outer tips of the shoots, from which new leaves, flowers and fruits sprout. Whereas an animal, upon reaching maturity, has almost no young cells left in its body, Dr. Raven said, "in plants the ends of the roots and shoots are always juvenile, always growing, always babies."
A plant is also always drinking, slurping water and nutrients the only way it can, through its roots. Everything needs water to survive, but another radical difference between the faunal and floral crafts is that while we can drink water and keep it circulating through the body via the bloodstream, water moves through a plant's body in a continuous stream, entering through the roots, crawling up the stem and evaporating out through little openings, or stomata, in the leaves. In fact, the upward tug of evaporation is what pulls more water up from the soil, as the clingy water droplets follow each other skyward through the hollow capillaries of the plant's stem and leaves, shinnying as high as 300 or 400 feet above ground in the case of the giant redwoods.
Plants other than those that hail from desert regions are not equipped to handle the absence of consistent moisture within soil. Soils that are so airless that they must be allowed to dry almost to the literal point of having no moisture at all present an unnecessary hardship to attempts to keep them alive in a pot. Soil that does not cause roots to suffocate, die, and rot are a much more easy alternative than trying to intuit airless soil.
The porousness of an unglazed clay pot can make a huge difference too, allowing roots to access oxygen all around the inside surface of the pot, not just at the top or drain hole.
There is nothing wrong with a plant that is just stayin' alive, not really growing larger but looking just fine, bringing enjoyment to its' owner. But if someone wants their plant to grow, maybe bloom if it's of a type that can, being stagnant with no more room for roots to grow is going to make it take longer, at best.