I just want to go back to a previous question:
Frank mentioned Shakepeare's, "I will be heard. And shall." It is clear that most native speakers today cannot express this precise idea using modal verbs exclusively. But they can express the precise idea using other words.
Are we to say we have lost a grammatical ability when the alternative is grammatically expressed?
Another thought. The German "Ich wäre dankbar" is used often to express the same idea as the English "I would be grateful". Modern German uses a subjunctive; modern English uses a modal verb. Does English, which has 'lost' the subjunctive here have the same grammatical ability as German?
These may seem to be hair-splitting questions but, unless we are discussing the same idea, then there may be some confusion.