EMPLOYMENT over the 20th and 21st century has gone from basic exploitation to socially responsible, aided by powerful unions -- and has perhaps toned down or regressed a bit from there.
Unions might argue that "toned down" is an erosion of workers' rights, and perhaps an example of going too far was the government's attempt to maintain zero-hour contracts.
Employment versus workers' rights is an evolving concept, a shifting power-balance between two extreme ideals.
One ideal is that all workers should love their jobs, be grateful for the opportunity to work, and will always try their best to work to what the job requires. The other ideal is that work is not always satisfaction, but it provides a means of survival, places food on the table, and as a consequence workers depend on it as a buffer from hardship.
The balance between these two ideals has tended towards the employers' side these days, supported by legislation. The 90-day rule is one example. There is a modern expectation of what employers have a right to expect, and also the broad idea that if a worker is a good worker, they have nothing to worry about, and would have work.
Thus the zero-hour contracts might have seemed to be the ultimate we-reward-only-good employees, but the reality was it was stacking the cards far too heavily towards the employer's favour and whim. The logistics for an employee to undertake work are personally expensive in themselves. And no one really lives from day-to-day when it comes to income, unless you're a beggar on the streets. Employment is more than just paying a robot for a service. It is a socially responsible contract that contributes to self-esteem of a person, the welfare of a family and well-being of a community.
An employer might argue they don't ever exploit their workers. But it is too easy for an employer, with one eye on the profit line, to be biased towards economy rather than welfare. And if the employment structure is in place, it'd be used.