So I’m not in America and might be able to offer some insight. Others have mentioned big box stores, online shopping, and lack of money as the main culprits. I’m fairly certain big box stores are not it, and the fault may lay almost entirely on amazon.
Where I’m from, malls are still the place to go for new things to buy, including electronics, clothes (of varying degrees of quality and price), drugs (the legal kind), and home decor. Businesses like Walmart (as in, supermarkets that sell things other than groceries) have shops inside those same malls. In the whole city, there is one standalone Walmart, in the emptiest part of town with middle-upper class suburbs around it. The one exception is Costco, which has two franchises in town, not inside a mall, but the demographic that goes there is decidedly middle class families and businesses.
We can order stuff from amazon, but it ends up being about the same in terms of cost, and takes up to a month to arrive. Money is tight for pretty much everyone at the moment, but we all still go to the mall from time to time, for one reason or another.
For example, I’m overdue a visit to get my eyes checked again, my glasses need replacing. And I’ll probably stop by the radioshack (yup, remember that?) and nab some rechargeable AAs.