According to Osho, enlightened genius never stops appearing; traditions stop recognizing it. When a lineage declares itself complete (like the Jains fixing twenty-four tirthankaras), the next awakened one simply becomes the first of a new series—Buddha would have been the twenty-fifth had the doors stayed open. So yes, someone of Mahavira’s stature can emerge today, though orthodoxy may not admit them.
Yes—great awakened people still come; if old groups won’t accept them, they begin a new path.