I think you’re missing the complexity of macros: they’re not just Rust or not-Rust, they can mix and match, including using Rust-like syntax. Take this macro stub for example (implemented as a procedural macro, if you want to make it harder):

  macro_rules! alpha {
      (
          $(<$($beta:ident),* $(,)?>)?
          for $gamma:ty;
          $(#[$delta:meta])*
          struct $epsilon:ident default $zeta:expr;
          ## $eta:tt // And I’m not telling you how I’m using this one
          $theta:item
      ) => { … };
  }

I can’t see any way to make this work with Analog syntax in such places as $gamma, $zeta and $theta (and who knows about some of the others like $eta?). I’ve made this a fairly extreme example, but simpler examples that are still problematic are widespread.