By your reasoning, all messages that one receives are supposed to be kept in your Inbox folder, as moving them around ensures you can't easily find all the email you've received.
That's exactly right. You'd prefer them to all go to the Trash, instead?
Creating subfolders to organize your communications is just making more work for yourself, and that's foolish.
It's interesting that you try to put words in my mouth, since that's not what I said. Clearly, you don't know how the concept of email works, or even how Mail works. You should study the Help files.
There's absolutely no good reason to move any email out of your Inbox. You can use Smart Mailboxes to organize your email in such a fashion, but the original email is still always in your Inbox.
Kurt: Clearly, you are an obnoxious, presumptuous idiot.
My IMAP account contains over 3.6 GB of material, consisting of over 100,000 messages and their attachments, covering the past eight years. Your proposal to hold all of that material in a single pair of folders — Inbox and Sent — can only be described as absurd.
Smart Mailboxes are not a solution for my needs. They may be "smart" enough to look at objective characteristics such as header folders (To, From, Subject, etc.), but they cannot interpret meaning, context, or purpose. Moreover, Smart Mailboxes cannot be organized hierarchically, but only in a flat (one-level) filing system. They also don't exist when I access my IMAP account via a Web-browser interface, as I do when away from my own computer.
Here is a snapshot of part of my mail-folder hierarchy, which is organized as many as four levels deep. This system meets my needs very well.
Kurt: If you have nothing to say that constructively answers the question I posed, then STFU and go away.