Treating or potting outdoor plants the same way you pot indoor plants doesn't make sense, so this continuing discussion doesn't have a solution.
This may have started out as a conversation about how bonsai are potted, but it has evolved to how traditional houseplants are potted/cared for. People still do it wrong because not many people read-up on it before they pot their one houseplant, they do like Mom did. Pots in a situation where the water needs to be confined by some means so it won't run out on the carpet. Pots out in the yard can be hosed down and excess water can drain out any which way. The two are different and require different methods.
One way of insuring that the plant doesn't get too much water (or, that it doesn't stay too wet, too long) is to provide a "drainage zone" separating the excess water from the soil. As usual, the solution to one problem just causes another, different problem. That solution causes the dry core problem. Another solution might be to provide a volume of water that soaks into a pot full of soil without draining out the bottom because the soil is still damp enough to uptake rather than shed liquid water. But, that takes planning and intelligence, like watering on a schedule a given amount before the whole mass is over dry. 15 to 20% of the volume of soil every 3 or 4, or 6, or however many days. That would be done on a calendar day basis. Every third day means every calendar day that is divisible by 3. It's a lot easier to look at a calendar and see if the date is divisible by the number of days that works for a given plant than trying to remember if you did it 2 or 4 days ago. Small pots have to be watered a lot differently than large pots, on a different schedule. It's easier to just pour water in and see it drain out and say, "I watered it". Checking the soil every so often leads to spotty results.
You're all missing the purpose of the terracotta pot: it wicks excess water so that it can evaporate sideways through the entire pot surface. As long as it doesn't have a "drainage material" zone it also allows the water to stand in the pot long enough to wet-out the whole rootball which is important to providing a usable interior growing medium immediately under the crown, often a dry zone where nothing can grow. The drier that zone, the longer water needs to sit in the pot before it runs out the drain. That is a common problem in houseplants where the pot is as wide as it is deep, and especially if there is a layer of "drainage" material at the bottom of the pot and it is sitting in a drainage tray or jardiniere. The water can run down the perimeter of the interior, wetting-out the circling roots without being absorbed into the dry interior core, so the drainage layer, which is intended to prevent the plant from sitting in a pool of water, does its job. So, instead of sitting in a pool of water long enough to wet-out the entire rootball, it causes the core of the rootball to get drier and drier and becomes a no-growth zone. A terracotta pot standing in water wicks it up the side and keeps the mass moist, longer. Plastic does not.
