Miért írjuk az angol nyelvben az "I"-t, mint személyes névmást nagybetűvel ÁLLANDÓ jelleggel?

Idézem egy angol fórumról:

"The pronoun I began to be 'capitalized' around the middle of the 13th century. But this was not true capitalization. Note that it was long before the printing press: all texts were in manuscript.

Before the 11th century, the letter i was normally just a short vertical line, without a dot, ı. The j did not exist as a separate letter. When an ı was written as a separate word or mark, as the Roman numeral ı/I and the pronoun ı/I, or when it was the last one of a group of ı's, it began to be written elongated, somewhat like a straighter ȷ (without a dot). This elongation of the separate, single ı was probably done in order to avoid confusion with punctuation marks. That of the last ı of a group was mostly in order to avoid confusion between u and ıı, between n and ıı, and between m and ııı, which often look identical in manuscripts: from then on, such groups looked like ıȷ and ııȷ (without dots).

I believe that this convention of elongating the pronoun I had already been established by the time the dot was first used. Because a long ȷ without a dot looks much like a capital I—which has been written the same way since Antiquity—, it was later assumed to be a capital. (Incidentally, the dot was then usually written as a very short diagonal line above the ı or ȷ.)"