Your example about malls is actually common in Asia:

- Central and Aeon own malls;

- Tesco owns multi-story shopping complexes including banking, retail, fast food, etc;

- and for that matter, Walmart, Target, Costco, and some grocery stores in the US operate multiple smaller businesses inside, eg banks or fast food.

It’s really not that uncommon for a corporation to operate part of their commercial space as a subsidiary marketplace.

Walmart isn't directly competing with the Subway or bank that operates in the front of their store. There's not a second grocery store operating inside Walmart