That kind of cranes is very reliable, but in the real world they are used maybe 10% of their capacity [1].
In a normal building site they either do very few cycles per hour (at heavy loads) or a decent number of cycles per hour at a tiny fraction of their load capacity.
Even when you use them intensively (with concrete buckets) to lift/pour concrete, that happens for a relatively short time (a few hours) each day.
A typical cycle is 5-10 minutes and you don't actually have 12 or 6 of them per hour, each hour in a normal 8 hour shift and - with some exceptions you normally have 1 shift per day, 5/7 (it is rare that a site working with cranes operates 24/7).
Besides, in a building site you don't work when it rains, and you cannot work with cranes if there is a not-so-strong wind blowing (for safety reasons).
[1] no reference, you will need to trust my word for it, coming from some 30+ years experience in building sites
In a normal building site they either do very few cycles per hour (at heavy loads) or a decent number of cycles per hour at a tiny fraction of their load capacity.
Even when you use them intensively (with concrete buckets) to lift/pour concrete, that happens for a relatively short time (a few hours) each day.
A typical cycle is 5-10 minutes and you don't actually have 12 or 6 of them per hour, each hour in a normal 8 hour shift and - with some exceptions you normally have 1 shift per day, 5/7 (it is rare that a site working with cranes operates 24/7).
Besides, in a building site you don't work when it rains, and you cannot work with cranes if there is a not-so-strong wind blowing (for safety reasons).
[1] no reference, you will need to trust my word for it, coming from some 30+ years experience in building sites