Here in the Cotswolds we're spoilt for choice - there's at least one good food pub in pretty much every village. The same's true of the Yorkshire Dales, much of Mid-Wales, much of the South-West, and so on.
Generally in the ex-industrial areas it'll be less impressive. Pub food in much of the Midlands, for example, is essentially whatever's offered by the owning chain (often Marstons or Greene King). But it's not necessarily terrible, and there are some smaller chains who are pretty good (e.g. Brunning & Price). It's more a function of the fact that the pub is ubiquitous in British society - you wouldn't expect haute cuisine from a bar in the Midwest either.
I lived in the Midlands for half a year, and I've spent a good deal of time in the American rust belt as well (via a job where I had to travel a lot). A typical English meal is significantly more bland than meals served elsewhere in the world, and I think it throws people off who don't already have a relationship with it and therefore can't perceive it as comfort food. It took me months to warm up to.
That's not to say "food in England is bad". I'm ethnically Hispanic, and ended up eating a ton of Turkish food and Indian food during my time there, which was spicy, flavorful, not too common in America at the time, and awesome. And a full English breakfast with your friends when you're all a bit hungover is perfection.
To be fair for every Green Dragon (Cowley) or Tunnel House (Coates / Sapperton) there are plenty of tourist traps selling pre-made cook-chill food from microwaves or tired carveries.
I think the tourist trap pubs are largely restricted to the few honeypots - Bourton-on-the-Water springs to mind, but then I've had good pub food in both Stow and Broadway.
These are the places people actually live.
Thai restaurant upstairs, pub downstairs (where you can order the Thai food too).
Similar thing near me in London, very middling karaoke pub with pretty decent curry from upstairs.
While I've definitely had great food in pubs and I agree that London has spectacular food options, I'd still opine that across England as a whole, "good pub food" is the exception rather than the norm.