is it necessary to develop all the pieces in the beginning?

I am a beginner and have been watching videos to learn to play better. All GM say that you need to develop ASAP your knights and bishops and castle by the 10th move. I have been doing it and noticed that often my knights and bishops come under attack from pawns or I can't move my pawns because of knights or bishops. I lost many of times to players who did not develop ASAP and started atacking me with their Queen. So is developping and castling ASAP really that essential?

Yes but the way to do it is not always the same. What openings do you play?

Edit: I just looked at your latest loss against an Indian player in a 30|0 time control and I think that before you blundered your queen you played really well following those principles. 

                       There's a school of thought that says, you can always stay put, and let your enemy waste moves coming to you.

No. Beginners should do that mainly because they are told to go for open positions (such as those that arise after 1.e4 e5), where quick development is very important, rather than closed positions, such as those that arise in closed Sicilians or the Winawer Variation of the French Defence.

In Chess960, I'm losing far too often by rushing development and trying to castle early early in the game.

The more advanced you become the better you get at judging when a lead in development or space will matter. For starters it is always a good idea to follow the rule of rapid development and king safety- It will give you a better game more often than not, and give you a solid foundation for later.

It is difficult to win a game of football with half your team on the bench.