Not convinced that is the reason. VOR and VHF com are both VHF which is inherently line of sight for reception.
That was my first thought too A2, but upon further reflection it occurs to me that VORs have a significantly higher radiated output than comm transmitters used to broadcast ATIS. Possibly a factor in reception range also? One could also listen to KSFO ATIS on the Point Reyes VOR (*H class VORTAC, elevation 1340') too if I recall.
*courtesy of wikimapia