People will return and use rail despite the issues of the rail network. At peak times the Glasgow-Edinburgh bus is timetabled for 1 hour 23 mins - this is 30 mins longer than the equivalent train.
If you are cost conscious (particularly if you are on free concession journeys like U22 and over 60) and don't mind the additional time or traffic delays that can happen then that's fine, but rail will have the advantage in speed and journey time reliability. There are of course exceptions to this (Wick - Inverness) but if you commute between Glasgow and Edinburgh the coach will see you giving up a lot more of your day.
If you are cost conscious (particularly if you are on free concession journeys like U22 and over 60) and don't mind the additional time or traffic delays that can happen then that's fine, but rail will have the advantage in speed and journey time reliability. There are of course exceptions to this (Wick - Inverness) but if you commute between Glasgow and Edinburgh the coach will see you giving up a lot more of your day.