Sandals is as all-inclusive as you can get because you get wifi, tipping and top-shelf drinks along with gourmet food, and watersport rentals such as water skiing and scuba diving. The only extra costs are spa treatments, most off-resort tours, super-expensive wines, and experiences like a private one-on-one candlelight dinner. They are couples only so no kids
If one wants the best bang for their buck with an AI, check out AI resorts in the Cancun area although that isn't the "price gap" RCG is talking about as many are cheaper than cruising
With all that being said, there's a huge difference between cruising and AI. Yet one of the most common questions we encounter when talking to new cruisers is "You two have been to port XYZ before, where I can find a nice beach?"