This debate is excellent. You're both making interesting arguments without resorting to
ad hominem attacks. I do have one question for
@rockm, though. It's not to undermine your point, but to figure out how I can advance my own practice of bonsai.
If growing your own trees from seed is not the best source of raw material, then what specifically is the best source of material?
To put that same question a bit differently, every tree came from a seed. It either germinated on its own, or someone planted it. What makes it bad for me to plant that seed myself, instead of buying a tree that someone else planted a long time ago? Is it just a factor of time? If humans lived five hundred years, would your answer be different? Is it a matter of skill in laying the foundation for a future bonsai when the tree is young? If so, then shouldn't it be possible to learn that skill and then succeed at growing trees from seed? You say to start with better material, but what is preventing me from creating my own better material?
Again, I'm not asking a rhetorical question. I really want to know the answer.