You have to compare JavaScript with Scheme of the time when JavaScript was designed. Both macros and immutable structures are pretty recent (1999 and 2006 IIRC) additions to Scheme, previously such facilities were either non-existent or implementation-specific.
While Scheme's syntax superficially looks like it's data, specification does not imply that there should be accessible AST as list structure anywhere (in contrast to Common Lisp, which is specified in terms of list structures and algorithm to build them from text serialization)
And by the way: You have left off the one most important defining feature of Scheme: first-class continuations. And JavaScript really does not have them (I would say that this is completely reasonable omission for JS's purpose)
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You have to compare JavaScript with Scheme of the time when JavaScript was designed. Both macros and immutable structures are pretty recent (1999 and 2006 IIRC) additions to Scheme, previously such facilities were either non-existent or implementation-specific.
While Scheme's syntax superficially looks like it's data, specification does not imply that there should be accessible AST as list structure anywhere (in contrast to Common Lisp, which is specified in terms of list structures and algorithm to build them from text serialization)
And by the way: You have left off the one most important defining feature of Scheme: first-class continuations. And JavaScript really does not have them (I would say that this is completely reasonable omission for JS's purpose)