The statement that Hajj and jihad continue until the Hour means that their religious rulings remain in force. It does not require their practical occurrence continuously, at every moment or in every year.
An unforeseen calamity could prevent Hajj from taking place in a particular year. Likewise, there may be a period with no actual fighting. In each case, temporary non-performance is different from the cancellation of the underlying ruling.
This is the essential distinction for understanding both madiyan and the declaration that neither duty is revoked.