I'm not saying unlimited sick leave is the base cause, but it would be a significant contributing factor. As a business, you know how many employees you need to provide X function, and you resource and budget for that accordingly. You know the defined things you have to cover such as Annual leave, training etc and yes, an estimated coverage for a known and defined amount of sick leave, These are the things you can control, and manage. You don't have excess resources just sitting around if you don't need them. You have some of course, to cover the unexpected, but you are managing risk there. Unused, expensive assets are a negative cost. If you have a situation where some employees needed to fulfil your base function, in excess of those recognised and available to cover the known and anticipated shortfalls, are suddenly not available, at random and in numbers, for indeterminate durations they, not you control, how the hell do you manage that, especially in an occupation/industry where you can't just have a generic employee sitting on a couch for the day because he wasn't needed that day, you need x number of highly skilled employees sitting idly on various couches because of the specialised and segregated nature of the job. You're still paying them, whether they're needed or not, as are you paying the absent staff for however long they feel they need to be absent (there's no financial imperative to return to work - that's what drives it usually). You can't suddenly train and pay more staff to be available because of the nature of the job, plus there is no end to the requirement, and if suddenly there was, what do you do with the excess staff you now have? They all have to be kept trained and current, even if there's nowhere to use them. It's a logistic and financial nightmare.