For what it's worth they seem to have the right idea with the X19 currently, but only time will tell if it pays off.
Is Linlithgow that much further from Livingston than say Fauldhouse?, from my understanding I think Linlithgow is closer, but I know distance doesn't measure demand.
If Lothian were to take on the 31 route hypothetically, (presumly under a new route number) I think maybe that would be the only shot.
To be fair those two aren't the best examples I can think of, the X38 was definitely not the result Lothian were expecting I think, and don't even get me started on the Green Arrow disaster.