Play back singing and its relevance?

Friends, I have been hearing a lot of comments and remarks by mentors and others on the show that "this voice is very good for play back" or "this voice is very cinematic". Yet another time I heard some mentors saying "iski awaaz aaj ke film ke liye bahut suited hai" and on other hand good singing like from Dilshaad was moved aside by mentors and Janta alike as it was not felt to be contemporary.

So I was wondering that what is your opinion on play back singing in Indian movies? Whether "aaj ki movies" or "kal ki movies", I never found myself comfortable with songs in Hindi movies particularly when the hero and heroine are singing on train or public places or in mountain valleys, where one could hardly hear each other's shouts leave side the singing, nd yet they are showing singers singing the songs so clearly! What a contradiction! I heard one song in a movie where the hero is on the helicopter with earplugs and yet song they were singing, being so clear.

There are quite a few songs very appropriate like Hritik singing in Kaho Na Pyar Hai, the song on the stage and likes. I can even understand Raj Kapoors hanging on a piano and singing in a gathering but what about singing in a forest and even whispering is heard by the hero and likes? In fact there were many good songs in the background which created a very sombre feeling (which perhaps otherwise can not be by acting alone!), particularly by SD Burman (one which comes immediately in my mind is Vaha Kaun Hai Tera in Guide, there could have not been a better use of background singing than that).

But now it has become so common to inject a minimum of 5-6 songs even if situation requires or not but just to complete the 3 hours duration. If that is what these singers are aiming to achieve, it does not matter who starts singing eventually in the movies as if in the hall one uses that period of singing to excuse himself or if watching in home, press forward button (ever thought of watching a Hindi movie without remote?).

Recently private albums have started coming in the market and may be out of 100 there could be one or two which stand out.

But having said that old playback singers have done a great work and their songs are even till date so fresh, even if no one remembers the name of movie. But same can't be said for the recent movies where singing, lyrics etc have no relevance and are mainly to make the movies complete its duration. It has become very predictable in Hindi movie when there will be a song. I do not think that as many songs will be remembered in next 25 years of today, as we are and will be remembering songs of 25 years or even before. Those golden songs are remembered today and perhaps will be 25 years from now as well.

Please give your opinion as how important or meaningful is playback singing in our current movies and should we not get rid of this necessary evil to the extent possible?