We have become a passive society, waiting for something interesting to come to us instead of seeking out that which might be of interest.
In and of itself, entertainment is a necessary part of our culture.
It is a distraction from our everyday routine--something out of the ordinary that appeals to our love of music, literature, theatre, even laughter. I think we all need at least some of it in our lives--when it rises above just the popular, it can educate and uplift us.
But modern entertainment is delivered to us much of the time so we need do little to receive it--other than to push a button.
That has resulted in a diluting or "dumbing down" of so much cultural content that it's all pretty much pablum--easy to take, but not much going on.
So, yes we need entertainment in our live--just not most of the crap that finds its way into our homes and multiplexes.