The point is that the user can go to `m.wikipedia.com` and not do anything else. They don't have to hunt around for a footer option, they don't have to do multi

The point is that the user can go to `m.wikipedia.com` and not do anything else. They don't have to hunt around for a footer option, they don't have to do multiple page loads (which can cost some people money!), they don't have to keep some cookies around or use the same device for their preference to be maintained. Note also that WP isn't alone in their choice. Facebook, another website with a large non-Western user base, also maintains the same behavior. Go to https://m.facebook.com https://m.facebook.com, you won't be redirected to https://facebook.com https://facebook.com . There are tradeoffs either way, and no matter what WP does, they'll be making some users unhappy. Not all of these users fit the same profile, either. Wikipedia has a global user base, so what's best for most American sites isn't necessarily what's best for Wikipedia. Ultimately, it's not the case that one option is right, and the other is wrong.