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Earthbound telescopes would be able to take better pictures than Hubble if it wasn't for the atmosphere. Their tracking ability is very very very accurate, and they have optics much bigger than Hubble.
The Hubble is not pulled over, it is playing space pinball like everything else up there (and down here). It does not have the whole sky available to it at all times. It still orbits the earth, so parts of the sky will 'rise' and 'set' as Hubble changes location. Hubble can't see the whole sky simultaneously, its field of view changes over time, it is not fixed. For most targets, the astronomers wait for the object to come into view, then they take the exposure within the time available. During the time of the exposure, the target is moving in the sky, so Hubble has to track it using gyros, flywheels, and gizmos much like a planetbound telescope has to track its target as the earth rotates. For some super long exposures like the Hubble Ultra Deep Field with all the cool galaxies, they can take hundreds of exposures over many days and later composite them, but Hubble can't take one super long shot, the target is just not always in view.
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