The shall/will distinction for a future event was never natural for the majority of natve speakers of English.
I actually am one of those native speakers
—of American English
—for whom it has never been natural in speech. I could probably count on two hands the number of times I have dared
in live conversation to use
shall to refer (in a declarative, first-person clause) to a future event. That takes real courage! But
—and I'm sure you will (not
shall) disagree with me here
—I think it is a type of courage worth developing, insofar as the distinction can really be quite elegant. I say "can be" because I encounter many cases where neither seems better than the other, even in theory. Consider an example such as this one: "I think I shall take a walk." To the extent that any residue of volitional meaning is retained in
will as an auxiliary
—and I should (not
would) like to believe that there is some residue there
—it doesn't really make sense to say, "I think I will take a walk," which, at least in theory, represents the speaker as being unsure of his own desire! For another example, consider the distinction between "I shall never forget this day" and "I won't ever forget this day." The first sentence is stronger than the second. The version with
will is, at least in theory, rather similar to saying, "I hope never to forget this day." The version with
shall prophecies that the forgetting won't happen.