Prior to the Children of Israel receiving the Torah at Mt. Sinai they had one miraculous experience after another.   From the 10 plagues to the splitting of the Red Sea, they saw, they heard, and they felt the knowledge that all there is, is G-d and that nature is simply His creation that allows Him to conceal Himself.  

But what about us, who have never had experiences like this?   Are we also to be held to the same responsibility of fulfilling the Torah, as well?    Why doesn’t G-d just have a National Revelation every generation?   If He made His point 3300 years ago, wouldn’t it be even more powerful, if repeated for every generation to hear.