I have mentioned a couple of times that the first Stereo Boomboxes I recall seeing were Superscope units in Debenhams. Today Debenhams joined Beales (where I bought my Panasonic CD Radio Cassette) in the long list of Town Centre Casualties https://www.bbc.co.uk/news/business-55142724 Debenhams were struggling even before Covid. I do wonder if part of the problem is that Department stores no longer seem to stock any cool gadgets or other things of interest to most men. What with music, films, and banking all moving online, the last time I was in town was for Beales closing down sale and even then didn't see anything I couldn't get in TK Maxx who have a branch with free parking less than a mile from here.
Personally I feel like people love to go somewhere to shop, we have one of the world's biggest indoor malls here and several others that for years were packed. I do feel like one of the main issues with sales decline is inventory, like you say Longman, they have the same stuff at the discount stores. There might be some comparision to radio, once Clear Channel bought most of the stations in the USA, they consolidated local programming into the corporate office, now anywhere you go here, the radio sounds pretty similar, and boring. When Macy's bought Daytons (from Target), overnight they brought in the most bland, normal, safe clothing and sales dropped off a rock, the flagship store closed a few years ago here. When I travel and shop, I stay away from the big stores, it's all the same stuff now, 25 years ago it was fun to see what other cities or countries stocked because it used to be different.
One of the reasons they were giving is the demise of another chain of clothes shops Arcadia which had lots of concessions in the Debenhams shops. So like you say they were trying to sell the same stuff in the Department stores as in other shops just down the road. Funny you should mention Radio Stations as tuning around today I found that a station that had gone through three different brands (The Breeze, Jack FM, then Sam FM) has changed yet again into a new National chain "Greatest Hits Radio". I haven't listened enough to form an opinion. I have a bit of a love hate relationship with Smooth Radio which is another National Chain run by the same company who has stations like Classic FM (classical music's greatest hits). It was great to hear Will to Power for the first time in over a decade last week. Then two days later they played it again. I am convinced they have a playlist of less than 100 songs which they update every couple of months. Maybe the station is run using an old Seeburg or Wurlitzer Juke Box
I've been a avid radio listener forever, your probably spot on with the 100 titles being played, my buddy used to work in top-40 radio (bubblegum radio) and he said that was all they used back in the 80's. We do have some niche single outlet clothing stores here that seem to be doing ok, usually made in USA Clothing or boots, more expensive but classic styling that lasts forever. I've heard that Doc Martins are back on the hipster radar over here, I just checked their website and they do have some hometown manufacturing, the stuff they ship over here is manufactured off-shore.