Should is meaningless in this context.
You're saying that, under certain circumstances, the company should pass on savings to its employees.
Or maybe it should reinvest that savings into R&D in order to secure a more stable future for its employees.
Or maybe it should reinvest that savings into marketing.
Or maybe it should use it to hire more employees.
Or maybe it should use it to increase the salary of its CEO who successfully led his/her workforce into a new paradigm while increasing productivity and cutting costs.
There's a lot of "shoulds" in this world. Unfortunately, they're often mutually exclusive and usually subjective.
On the other hand, whether companies should have to pay for individual home office space is a reasonable question (They don't have to provide free lunch at work, they don't have to pay for the commute, both of which are just as or more important for you to be able to work in an office) and will probably largely come down to regulation and, in the absence of that, market forces.