Most tours are only a few hours time and depths less than 50 feet. You want large viewing windows, your own cabin (includes large bay window) for optional overnight excursions with meals included and diving to up 120 foot depth. As well as a great variety of locations to choose to explore.
Would you prefer such an extended underwater tour rather than just a few hours? Costs are pretty reasonable.
Or would your big attraction preference be the 3 day space tour if you had the spare millions?