The biggest reason is that there has been almost no productivity gain for cleaning a hotel in the last 20-30 years. It takes same amount of time and effort. So why would the wages go up if productivity is not up?
The productivity gains went to either things that got automated (e.g. speciality equipment operator - wages are higher but there are less jobs) or knowledge workers (software engineering salaries have skyrocketed).
The productivity gains went to either things that got automated (e.g. speciality equipment operator - wages are higher but there are less jobs) or knowledge workers (software engineering salaries have skyrocketed).