Ardwulf is writing about what MMORPGs could learn from Skyrim. One quote caught my eye: "A decent crafting system would be a good start. One of the more popular starting areas is a forest, for example – what if there was a lumberjacking harvesting ability and a tradeskill you could use lumber for, and you made trees – every tree, mind you – interactable? Well, obviously a lot of areas would be promptly deforested!" If you compare that with reality, you'll quickly observe that it took humanity many centuries, millenia even, to deforest most of Europe, using the tools typically available to somebody in a virtual fantasy world.
While Ardwulf is correct in assuming that if in a typical MMORPG it was possible to fell trees for crafting, and there was no corresponding tree growing mechanism, deforestation would be rather quick. But if you look at the root cause for that, it is that in a typical virtual fantasy world there are a relatively high number of characters per square mile, and a relatively low number of trees. People who are very concerned about immersion in MMORPGs often complain about teleports and similar methods of fast travel. But even if you remove all of those, you still end up with worlds where two major cities can be as little as 10 minutes on foot apart. I once determined the size of Azeroth as being only about 80 square miles.
When over a decade ago in Ultima Online I wanted to build a house, it turned out that there was no more flat space available in the whole world (on my shard) to build even a small house on, and I ended up buying a house on EBay. This still keeps most MMORPGs to offer freely place-able player housing: The total amount of square meters required to offer every player a house is often large compared to the total size of the world. Games with bigger worlds usually have to create these larger areas with algorithms, and often end up with areas that are empty and boring. But if you hand-make worlds with a density of content which plays well, you end up with virtual worlds which are very small. And so if you want to implement tree felling or house building, you don't have enough space for that.