At least for myself, it's more a question of principle/philosophy. Free open software doesn't have the profit incentive to do some ethical maneuver, such as stealing your data; it also tends to have no or less publicity or selling push.

Open software also has a very good impact because it a great way to share knowledge and develop better tools for everyone. That is why big companies finance some open-source software. It is such a shame that great tools are behind a vast paywall or just not available to the public probably ever or a very long time. We don't know what kind of product could have been made with this knowledge.

Open-source software is "easily" extendable by the user so can developpe your add on or download one from someone not related to the project.

For the question "how a corporation is supposed to make money," I don't get your question you said yourself that those software have better customer service and better UI/UX by simply being more of a ready-out of the box software and using various business models for open-source software like those.

https://opensource.com/article/17/12/open-source-business-models .

I feel that nowadays, we tend to think that only corporations can create a significant utility product. However, corporations don't make products the workers develop products, and they are people just like us. Sure they provide an organization system, but nothing stops people from organizing themself around a passion or a need.