I don't have a chip in my shoulder, and I do collect trees every year! I am taking off work this coming Monday to go to the Swamp looking for BC and Water Elm as a matter of fact...
My point is that collecting in the states leaves you very limited choices of suitable species for what we do, and some locales will have more than other obviously. On top of that, finding suitable material that is of a suitable size with decent movement... can be down right impossible at times! I am a variety kind of guy personally- I like to think of myself as both a collector and to some degree an artist. I like the big wedge shaped BC we get out of the swamps, but I also like Shohin Azaleas- Or Chuhin sized informal upright JM, Trident Maples... Maybe a well styled twisted old Shimpaku or JBP with a honker of a trunk and some deeply plated bark... you cannot find any of those trees growing indigenously in the US. You may stumble across one every now and then in someone's YARD, but not naturally occurring in the wild.
Collecting is a fun, inexpensive way to get material, but for people looking for stuff not available in the woods beside their house- ordering online is a great opportunity and one that has only really started to become more popular in recent years.