Should the good writer be able to write on every topic?

Yes and No!

Yes, because writing is a art that can be mastered with practice and exposure to the subject in question, adding color and creativity can build up as you grow.

No, the new generation (millennials and younger) are too judgemental as readers.

Yes. A good writer should be able to research and write on any topic; however, that does not mean the quality of their writing will be the same with every topic. That will depend upon the expertise of the audience they are writing to and the depth of the writer’s knowledge and research.  Two important keys to good writing are quality research and the ability to synthesize that research into a coherent topic; at the level of the audience they are writing for. A good writer should be able to do that no matter what the topic. Never be hesitant to try. I had to write a paper and give a lecture on it to a group of civil engineers. I knew nothing about engineering. After researching the topic of discussion, I was able to write a paper from an outside perspective. Because the engineers are immersed in engineering they had not thought of this viewpoint before. It was very successful and opened up much discussion, as was the intent. I say “broaden your horizons” and have confidence in your abilities. The more one tries, the better they get.

its like your saying that your right hand is the same with your left hand :)

So a good photographer also have to take every picture perfectly?

No. That is impossible.  No man is knowledgeable of EVERYTHING in this world, only God is.  This means that no matter how good a writer you are, you cannot cover every topic there is in this world.

In my opinion ,No!! ,every writer has his own field ,love ,anger ,poletics social issue ,every writer can't write everything