Why does my iPad automatically capitalise Bono but not the edge?

Can anyone please tell me why my iPad automatically capitalises "Bono" but not "the edge"?

English is hard.

One is easily distinguishable as a proper noun. Bono is not a common word that would be anything other than a name. Like Sally or Andreas. The OS can capitalize occurrences of Bono with a high degree of confidence that you were referring to a proper noun.

The other is not easily distinguishable as a proper noun. There is no way to tell if the sentence:

I played guitar near the edge

is referring to you playing guitar near a precipice or near another human who has the legal name Dave Evans.

You can create a text shortcut to automatically expand a text snippet you enter like tedge to The Edge if you like. You can find shortcuts in the Settings app under General > Keyboards > Shortcuts.