What we are seeing in the developed world now is a hyper sensitivity to measuring productivity within an organization. Technology and specifically spreadsheets and algorithms now allow the precise measuring of assets against a desired level of productivity relative to benefits offered to the employee. The OP’s question points directly at pushing this model in favor of more satisfied well being on the part of the employee.
I have experienced a variety of situations over the years as a staff designer, manager, freelancer, contractor and educator. Where I have seen the most HR efficiency applied recently to the organization is in the education sector. Here in Korea (which borrows many HR and corporate policies from the USA and Europe), the number of hours you teach is specifically controlled to define your status as either part time or full time. The number of full time positions are tightly controlled (i.e. minimized) to keep the benefits offered by the organization to a minimum. The term that is used is called ‘casual labor’ on the adjunct/part time side. This allows for schools to increase their class sizes (i.e. more revenue) but keep a minimum of full time staff that ding the bottom line on expensive pensions and benefits. Most of the classes are taught now by part time adjuncts who usually have 2-3 teaching/contract gigs a different schools and is very low on the well being scale. Here in Korea this issue was brought to the highest levels of government and changes were made to hire more full time professors in all areas of education in order to alleviate the deteriorating lifestyle of the adjunct professor.
The idea of hiring more full time employees at a reduced number of hours indeed benefits the lifestyle of the employee, but it must be balanced with policy and heed the laws set out for full time benefits collecting employees. Whether it is a design or manufacturing firm, university or multi-national conglomerate, this is why freelance and contracting is a reality in the marketplace. When there is a need for a specific task or service, the firm hires the resources to fill the scheduling/resource gap. What the OP is suggesting challenges many policy laws that determine how a ‘full time’ employee is defined by the government and its income tax and benefits laws. I surmise you will need to roll up your sleeves and dig into your state’s HR tax and benefit laws to understand how much latitude there is to change the rules.