And the newcomers don't stay too much.
Yes, but look at these newcomers. Lots of them never considered starting bonsai but got one as a gift. They have no idea what's involved. And honestly, I think giving a bonsai is not a good idea. You wouldn't buy someone a puppy, if you don't know if they want one and can take care of it.
These people do not stay. They didn't want to do bonsai in the first place.
Then we have numerous people who buy bonsai kits, plant seeds or yank seedlings from the ground and are surprised that things do not work that way. Of these people, very few understand that it will take much more effort than that, including study, training, trying and failing, and many years before you can grow something worthwhile. Of the ones that proceed, many fail and give up. Only a few of these people stay and become bonsai growers.
So, out of 100 posts from new people, only 1 probably is really interested in the art. That's why only a few stay.
Clicio, I understand your remark about Adobe forums and the repetitive questions there. But at least, on these forums, the questions are about Adobe and not about MS Notepad.