I’m really confused by what the goal or point of the original post is.
I’m sure part time can be done but would vary greatly on size of company and responsibilities. A part time professional is usually called a contractor. They are used when needed based on their specialties and skill set but not to lead a project part time. Professionals that want a part time job or flexibility usually go this route.
What’s the incentive for an employer to hire 4 part time professionals when 2 can do the same amount of work and be there the whole week to address any issues and deal with the rest of the world that works 5 days a week? Unless your salary is 2x the normal salary, why would you only want to work 2-3 days?
Again, I’m just confused by the post. If things get really busy at work would you (as the employer) hire another part time guy or would you rather have a full time employee? It’s like filling 2 glasses half way just to have a full glass of water…