I admit to being a food snob and regularly lunch or dine out in places such as Le Gavroche, The Wolseley etc
Wetherspoons is in a different category but, in my view, provides excellent value for money. On the rare occasions I go, I order the gourmet steak meal, which comprises a large sirloin, which is cooked fresh and to my liking (rare), and comes with a peppercorn sauce on the side, baked potato or chips, salad, peas, mushroom, onion rings and tomato, with a glass of wine - for about £12!!! The quality of the steak is fine and, on the one occasion they overcooked it, they happily replaced it with no argument. I have eaten in much more expensive restaurants where they have overcooked steak and been less accommodating about replacing it.
It provides a wide range of choices for people on a budget (or not on a budget) and, especially during weekends and school holidays is often full of families and students rather than the clientele you describe. During the week, it provides a base for work colleagues to mix, at a price that everyone can afford, no matter what their position in the company etc. I don't think that the quality is any less than that provided by other chain restaurants where most of the food is prepared centrally and reheated such as eg Cafe Rouge etc. There is also something comforting in knowing that, wherever, you are, the menu is the same. They also helpfully publish allergens, calories etc on the menu.
Also, some of the pub buildings are beautiful, especially in London, often based in historic buildings, such as Crosse Keys and Knights Templar, or the one in Ramsgate, which is the former Royal Pavilion and is literally on the beach. However, I can accept that other branches may be different, are based in scruffy buildings and have a different clientele, which presumably reflects the locality.
But you wouldn't catch me in Tescos or Morrisons cafes, even if you paid me, utterly depressing places. In fact, I have avoided Tesco altogether since they were found to have included horse meat in one of their own products, arguably even a worse transgression than supporting Brexit.....!