I think the problem is that you're not thinking about searching in a way that's congruent with the way isearch has been designed to work, and so your question doesn't really make sense within the context of isearch as it currently exists.
Isearch does already give you exactly the feature what you want, but you have to tell it that you want it to happen by typing that C-g you seem so vehemently opposed to typing. If you don't tell isearch what you want to do, and when you want it to do it, how is it supposed to know what to do?
As @Tom tried to explain, the default way isearch starts from the current position in the buffer, and can restart at the beginning of the buffer if you've typed some failed characters and then press C-s, is a very valuable feature. I'm sure many people rely on this behaviour. Your method of using a macro to always start an isearch at the beginning of the buffer would confound and confuse many of us, though of course it's not a bad thing for someone such as yourself who is accustomed to it. It does mean though that the rest of us are quite confused by your dislike for having to press C-g to delete the non-matching text.
Think also for a moment about what a second C-s does if you press it immediately after starting isearch (any time but the first time in a session) (i.e. before you type any other character). Note in particular what happens if your previous search string would only partly match something in the current buffer, and then you press C-g (and also note how the failed search string is presented, regardless of whether it would partly match something in the current buffer or not).
Think also about how your feature might adversely affect the use of multi-isearch-next-buffer-function.
Claiming that other editors can do what you want isearch to do in emacs doesn't really help your case much.
I think what you really want is some slightly different type of search function which only allows you to search for text that it is possible to find in the current buffer, instead of isearch's ability to search for anything whether that text happens to exist in the current buffer or not.
Perhaps isearch-mode could be adapted to do what you want it to do, but one way or another I think you'll have to write some elisp code. Perhaps you could implement your new search mode as an option within isearch-mode that can be toggled on and off in the same way case sensitivity can be toggled on and off; and that can be set by default, again in the same way that case sensitivity can be turned on or off by default.
