You’re not understanding this correctly though, let me rephrase.
I own a business and I have 30 employees who I offer insurance to now. The reason I offer them insurance is because I want my workforce to be healthy and happy. It costs me on average $10,000 per employee for this benefit. Now suddenly everyone gets insurance regardless of whether I offer it or not, so there’s no need for me to do so any longer. It is easier and cheaper for me to simply pay the fine now rather than provide insurance because I know that my workers are still going to be covered.
Businesses provide insurance now because it’s the right thing to do and a healthy workforce is a productive one. But if someone can get similar coverage from an exchange and it saves the business owner a lot of money, they are very likely to do that.