A hotel gym is a controlled experiment in what equipment is actually for. Someone has spent real money to fill a room, and the room still does not work. Twenty-three years of those rooms teaches you more about equipment design than any showroom does.
What is always there, and always useless
Three treadmills, two of them out of service. A cable machine with one attachment. A rack of dumbbells that starts at 5 lb, climbs in 5 lb steps, and stops at 30 just as it becomes useful. A mat. The pattern is consistent enough to be a law: the room is furnished to look equipped, not to be trained in.
The three constraints that actually bind
Floor area. Every machine claims a footprint permanently, whether or not anyone is using it. A room with six machines has almost no floor left, and floor is the one thing every bodyweight movement needs.
Adjustability. A fixed 20 lb dumbbell serves the narrow band of people for whom 20 lb is the right load today. Everyone else is either under-loaded or unsafe.
Maintenance. Anything with a cable, a pin, a bearing or a screen will eventually be out of order, and in a room nobody owns it stays that way.
The equipment that survives an unattended room is the equipment with nothing on it that can break.
What that implies about buying anything
The lesson is not that machines are bad. It is that the value of a piece of equipment is its usefulness divided by its footprint and its failure modes. A rack of dumbbells scores badly on all three counts: it eats a wall, each pair serves one load, and the rack is the only part that cannot fail.
Judge anything you are about to buy the same way. How much floor does it hold hostage? How many loads does it cover? What on it can break, and what happens to the rest when it does?
The version that worked
The thing that ended up working in those rooms was not in the room. It was whatever could be carried in, set on the floor, used for forty minutes and set back down: a bag, a block, a bench that happened to be the right height. That is a narrow specification, and it is more or less the specification the box was built to.