I am not getting it.

In sharecropping (with a lot of nuances depending on the specific countries and even different regions in a same country) the landowner and the tenant were some sort of partners, both had all the interest in having a better/larger crop (or raise more cattle, etc.).

In a normal capitalistic employer/employee relationship, the employees have no particular interest in the final outcome, they are only scared of being fired if they don't meet some (often arbitrarily set) "productivity goals".