The alternative explanation is that the employers have investments in corporate real estate and don't want their investments to lose value. Personally, I think that the the people at the top probably have investments in corporate real estate, while middle managers are the way you describe.

I don't think the people at the top usually care what the employees are doing so long as they're making money, and being in the office means they're keeping corporate real estate prices afloat. As such, being in office makes money for the executives, even if that money isn't made directly through the company.

Middle managers on the other hand, likely don't have any significant corporate real estate investments, nor are they as likely get significant bonuses for company productivity. As such, it makes more sense for their motive to be more about control than it is money.

That said, I do know some executives do indeed see employees the way you've described them; an infamous example comes to mind about the Australian real estate executive talking about how they needed to bring workers to heel and crash the economy to remind workers that they work for the company and not the other way around. I'm just not sure that many executives actually think about their workers in that much depth. I think if they did then we'd see a stark contrast of very ethical companies and highly abusive companies instead of the mix of workplace cultures we have now; because some ceos would come to the conclusion that a happy worker is a good worker, while others would become complete control freaks.