That would be pretty amazing, since a large number of the trains only stop at Falkirk, Polmont and Linithglow - unless you were thinking that Haymarket isn't Edinburgh...
By Intermediate stations I don't mean that 50% of passengers are making Falkirk - Linlithgow journeys.
My understanding is that if you look at all the journeys on the Edinburgh - Glasgow Queen Street services then it looks something like this:
Group A - 40% passengers:
Glasgow Queen St - Haymarket / Edinburgh
Group B - 50% passengers:
Croy - Glasgow
Croy - Haymarket / Edinburgh
Falkirk - Glasgow
Falkirk - Haymarket / Edinburgh
Polmont - Glasgow
Polmont - Haymarket / Edinburgh
Linlithgow - Glasgow
Linlithgow - Haymarket / Edinburgh
Group C - 10% passengers:
Intermediate journeys / Going through to somewhere else.
Those numbers are not exact and not recent but a few years ago I had some involvement in a project looking at related issues and they were something around that ballpark.
So the point is that each of the intermediate flows is relatively small but together Group B adds up to more passengers than those making the end to end journey.
6tph service is only of any help to Group A. Faster end to end journeys by running non stop are only of use to group A. If you have to slow down journey times or lose clockface timetabling for intermediate stations to deliver that 6tph service then it may be you are making things worse for Group B which is bigger than Group A.
I haven't had any involvement in recent timetable / business case work for EGIP so I don't know if this is still the case but certainly when EGIP decisions were being made this is the sort of thing that needs to be taken into account. Headline journey times from Edinburgh - Glasgow are important and we all want to see more and faster services, but it does need people to step back and actually look at where demand is generated.