Take the perspective of the employer. They receive cash from the sale of goods and services. They have to divide up that cash to spend on the ingredients needed

Take the perspective of the employer. They receive cash from the sale of goods and services. They have to divide up that cash to spend on the ingredients needed to run the business: real estate rent, supplies, maintenance, and labor. Labor can be subdivided into categories like salary, bonus, medical insurance, 401(k) plans, etc. In the status quo, 401(k) plans exist and have certain tax advantages, so employers feel compelled to make contributions to the plans. But if you pretend there's a universe where 401(k) doesn't exist at all, then the employer will just have to allocate that cash towards something else - like paying higher salaries, buying better office facilities, or whatever. Here's a real-life example from a ~10-person startup that I worked for. The company was debating about whether to purchase group health insurance benefits for us. The employees casually talked about how much they actually spent on healthcare each year, and we realized that our average spending was significantly lower than the average cost per person that the company would pay to enroll in the plan. So we agreed to decline the plan and asked the company to focus on cash compensation. Remember, money is fungible and there's no free lunch.