My parents ran a small hotel associated with a major chain and you don't know what you're talking about.

There are multiple models used by hotel chains for years. Some lease properties that they brand and run. Some get paid to manage properties owned by third parties. Others franchise to property owners. These models are vastly different from what Airbnb has. In every case the hotel chain has a lot of control and the inventory locked in.

Airbnb has no control over its inventory and doesn't own anything. The risks of this are huge.

Btw Marriott still owns a couple billion dollars worth of real estate.