401k, how does it benefit your employer?

So your company matches a percentage of your contribution to your 401k.
I have heard the speech from my employer's 401k representative of how a 401k will benefit "you the employee" but when I asked how does a 401k benefit the employer the answer was "Your employer sets up a 401k to show it's appreciation for it's hardworking employee's and that's also why they match part of your contribution"
I then asked " The company that handles all the investment made to the 401k, how much money do they make?
What do they charge and who pays that fee? I never got an answer to my question, just the initial speech again. So how does a 401k bebefit a employer. I would think they would have to get some types of deductions that would make it profitable for them. After all, nothing is truely free.
That sounds like the answer my boss would give. I want to know the $$ value.The dedeuctions. Example, no company is going to pay you more money then you earn them. If they did they would go out of business. So if they match your 401k they have to make it up somehow. I want to know how.
Thank you