How is mining profitable? The miner that creates a block gets the reward and all the fees that are in that block.


What happen with other nodes that does not create a block. In their case, will not they  get any reward and also any fees? How do they survive?
As I understand, when a block is created, all the miners start again finding the solution to create the next block. Can the miners choose which transactions validate? If it is like that, all the blocks in that time frame, are they the same?


Thanks!
What happen with other nodes that does not create a block. In their case, will not they get any reward and also any fees?


They will not get any reward for that block.


  How do they survive?


By finding other blocks. Blocks are mined, on average, every 10 minutes. That means that a miner has a chance to find the next block if they don't find the current one. Blocks are fairly frequent, and the miner who found one block is not necessarily going to find the next one.


  Can the miners choose which transactions validate?


Miners can choose which transactions they want to include a block. They do not get to choose which transactions are valid. It is not the miners' job to dictate what transactions are valid. All transactions that they include in a block must be valid, and they can choose any valid transaction to include.


  If it is like that, all the blocks in that time frame, are they the same?


No, they are not. Miners may choose different transactions. The transactions may be in different order. Miners also have full control over the coinbase transaction which is the first transaction in the block that pays them the block reward. This coinbase transaction can be modified by the miner, and typically is modified in order to have more possible blocks for them to try.

Furthermore, the coibnase transaction for different miners will always be different as they will want to pay themselves, not someone else. Thus the blocks will always be different.