Remember too that the scout ship doesn't have to have gear down. It can float 3m above the ground on its repulsorlift engines and have full ventral turret coverage. Yes, repulsorlifts can do this for a long, long time (they are highly efficient and use a minimum of power). The ship only has to land for a few minutes at a time to change shifts (and even then can just drop boarding ladders).
Keeping a ship in the air constantly running would be a maintenance and supply nightmare. Even keeping one constantly prepped for launch would be a huge maintenance problem unless the base has enough ships to rotate which one is on standby, I would say at least two or three ships off standby for every ship that is on alert. Than of course theirs the issue of having enough trained personnel to keep a crew on constant standby. And I don't know much about Imperial standby rules but I know in US carriers craft considered on alert are supposed to be ready for launch within five minutes. A lot can happen in five minutes in a real battle or a Role played battle..
You underestimate the technology. If the ship can operate for months at a time just with onboard consumables, then parking it on repulsorlift is nothing. Read the Wookieepedia entry on Repulsorlift.