It is not a good deal for the U.S. government to allow people to stay in the U.S. as permanent residents and never become U.S. citizens. As a PR, you are entitled to live/work in the U.S. permanently but you are not obligated to perform jury duties, etc. It is privilege without obligation in your favor. This is why the U.S. is motivated to approve most N400 applications. If your N400 is denied due to administrative issues, then address these issues and re-apply or appeal. In this case you are still a U.S. citizen material and t simply want you to tie up some loose ends. On the other hand, if it’s denied due to t have determined you are not U.S. citizen material anymore, e.g. crimes, false info in your Green Card/ citizenship applications, then you can expect that t will follow up to revoke your Green Card too. As I said it’s a bad deal for the U.S. to allow you to live here permanently as an alien. A PR is like a U.S. citizen in training. If the government has determined t will never make you a citizen, there is no point to train you anymore.
Anyway, thank you to all these Indian-visitors who help me out by giving their valuable help.