^lol you are repeating yourself . You are discarding the possibility of user error when people do it themselves, it's not that some people "can't" do a good job with it, it's that a poor soldering possibility exists.
And the second point that is escaping you, most people nowadays use banana plugs that DON'T require a solder, when you tighten two screws or fan out the copper stands, that's NOT a solder. This kind of connection is not as solid as factory terminated plugs.
Most of the separately available banana plugs nowadays you find on amazon like sewell, nakamichi etc. just have a mechanism for 'locking in' the copper cable, either by a set of screws or by fanning out the copper strands and tightening a metal piece over them.
Compression type fittings work just as well as solder. There is no study that proves otherwise. As long as there is good contact they are the same. Using bare wire is just as good too. There is no magic in cables.
-To be an audiophile you must abandon all research and science.