Sure, the "fair" rate at any point is whatever the market will bear. But a good baseline to determine the value (not the price) of such a good is to see what the lowest price is, that is, the price at which it won't go below. That price ratio is probably a good indicator of relative value. So, for example, the GH can be regularly be found at $200 during weekends and other low periods (e.g. Christmas Eve), while the St. Regis doesn't go much below $400 or so even in those periods. So that's the baseline value comparison between the two hotels, and sounds about right. All-in the St. Regis is probably "twice" as good a hotel as the GH.

So when market demand spikes (during a show or conference), prices of course rise, but if you're going to pay a multiple of fair value, you want to leave as little as possible surplus to the seller. In this case, the GH is charging you 6x the fair value (i.e. think of it as it "selling" you 1 room for the true value of six), while the St. Regis is only "selling" you 1 room for the value of 3. The dollar differential may be the same ($1,000), but those $1,000 of surplus captured by the hotelier are much more profitable to the GH than to the St. Regis given their baseline fixed costs (which determine the value price at the lowest point). Makes sense?