How would it even be possible with the need to serve Old Oak Common as well? There would surely be too much in its way for a junction west of there. Presumably any Crossrail to WCML plans involved a junction nearer to Ladbroke Grove.I would, as passive provision for it was not included in the Crossrail Act.
That’s not to say ‘never’, but providing for it would be rather disruptive, both to the GWML and WCML. For not much benefit, not least that there aren’t many of the right type of services on the WCML that could use it.