Macros aren't solely used to implement high-level features, mind you - in CL they're introduced without much hassle to work out gruntwork as well precisely because an elided form in s-expressions seems just as natural as the original forms.

Although that level of fragmentation you do talk about is plausible - I'd find it simultaneously disheartening and worth a bit of a chuckle. (I'm reminded of all of the concurrency abstractions CL seems "capable of" hosting with minimal friction - but none with definite thrust.)