Consider that people rarely say, "Hey, let's get some English food tonight." or "I really feel like cooking something English." There are few restaurants outside of England that specialize in English cuisine beyond "Pub Grub" or maybe the English (or Irish) Breakfast.
One factor is that of familiarity. The United States, Canada, Australia, and New Zealand have cultures that are heavily derived from English culture, so English cuisine isn't exotic enough to stand on its own in these countries. The New England popover is Yorkshire pudding. The Australian pie floater is a meat pie floating in a bowl of pea soup - Both of those elements are obvious English imports.
Those are some of the quirkier derivatives, too... Pancakes? A sandwich with sliced white bread? A baked potato with toppings? A main course of roasted meat with mashed potatoes, stuffing, and boiled vegetables on the side? Why make the effort to drive to a restaurant, endure the wait, and spend your paycheck on stuff that isn't much different from last night's leftovers? Even taking into account those who are too tired (or lazy) to cook, English-themed restaurants would have to compete with diners and chain restaurants serving such "normal" things (pancakes at IHOP, roast beef sandwiches at Arby's, fried seafood at Red Lobster, etc).
As for the rest of the world, that simmers down to immigration patterns as well as colonial influences. Immigrants from England gravitated toward those countries with very similar cultural heritages, unlike immigrants from, say, China, Mexico, or Greece. You're not going to see many English restaurants in Seoul for the same reason you won't find many Congolese restaurants in Vladivostok. This is discounting the global fast food formula, of course, which usually draws from ethnic elements but is simplified in a way that it doesn't need much cultural knowledge to be replicated ("Italian" pizza, "Mexican" tacos, "Mozambican" peri-peri chicken, etc). Pizza restaurants may be common in Chinese cities but they're not as much an emulation of Italian pizza as much as they're an emulation of the American fast food emulation of Italian pizza.
There's also the colonial element. India has a distinctive Anglo-Indian cuisine that might seem wildly divergent from traditional English food from a Western perspective, but is the difference between the two really that much greater than the distance between traditional Chinese cuisine and the average Chinese take-out place in any Western country? West Indian food is heavily English-influenced, too - Hello, Jamaican patty. Even in those parts of Africa that were once British colonies have adopted English foods... Scotch eggs are popular in Nigeria.