In America, there’s like 3 different things you could call a mall. When most people talk about them, it means a giant building with central indoor paths connecting a bunch of businesses. Typically, there would be a handful of “anchor” businesses, like department stores and a movie theater, and then space for a bunch of much smaller businesses in between including restaurants. These malls (at least the ones I’ve been to) for whatever reason don’t typically have grocery stores. I have seen pharmacies and small Dr’s offices in them.
Then there are “strip malls” that are typically a row of businesses on one side or surrounding a big parking lot. Typically grocery stores are in those.
Lastly, there’s “outlet malls”, which are often set up like a fake town with parking distributed throughout. They are commonly built on cheap land in the outskirts of towns, and they have mostly clothing. They are typically brand specific stores (e.g., Nike), so they are allegedly cheaper.
It’s that first category that Americans are going to be talking about if they just refer to a “mall”, though. The idea to have all your shops in a convenient place has been around forever, and still works great in many traditional business districts. The “shopping mall”, though, was somewhat of an artificial movement in the 80’s and 90’s that was always a bit destined to fail. Like people have said, the internet is partially responsible, but malls were hurting before the internet started really doing damage. In America, you basically have to drive everywhere, and if you are driving everywhere, it’s easiest to just drive directly to whatever shop you need. With malls, you have to park far out in a giant lot, and walk a long way to get to whatever business. You could call it lazy, but if you’ve only got a little bit of time after a day of work to do shopping, are you going to do the option where you get the task done in 30 minutes, or an hour?