Can lay people acheive enlighment (Arahanthship) in this life by adhering to Buddhist principles? During the time of Buddha, it is said many people at one gathering attained enlightenment by listening to only one one of his sermons. How can a  mind develop such a achieving  within matter of hours.  There are millions of devoted Buddhist in the world now but I have not heard a single person achieving higher mental status. Are there any other explanation this other than karma?
If you analyse the Sutta, you will find those who became Arahants by just listening to discourse are people who have already perfected Sila and Samadhi. For instance Buddhas first disciples, five ascetics.