They're the only huge brick and mortar electronics store still around....
Wrong.
The reason why they're failing is because the "big" things they're selling, such as household appliances (washing machines / fridges / televisions / home theater / etc) are heavily competed against by larger department stores like Sears, who have much better market outreach, advertising, and brand recognition.
The "small" devices get a lot of competition from the larger supermarkets. So their phones, tablets, various bluetooth accessories, DVD/Blu-ray players, etc are often sold at places like Wal-Mart or Target, for cheaper.
The media area has largely been shit for a long time. Not only are more and more people watching streaming movies / listening to streaming music these days, but their games business is and has always been crushed by GameStop and Amazon, and also the fact that digital sales are on the rise and phyiscal sales are going down.
When it comes to computers, Microcenter, Fry's, and other places absolutely crush them, and people are buying computers less these days because the computers they have last longer.
They've got literally nothing that you can't get elsewhere for cheaper or in a more convenient area.