Perhaps so that none will have any excuse when they finally stand before the Lord on Judgment day. Nobody can say, "Why didn't you tell me" or "I didn't know"
Could the person who has a hard heart (pathway), or lots of obstacles in their life (rocky ground) or lots of worries (among the thorns) come to God through just one tiny seed that they hear or see?
I think so. God is generous to a fault for he wants all people to come to him.