It is a writing technique called ‘fronting’. It it usually used to make things more dramatic. ‘The fake niceties and verbal webs of politeness are gone’ has the same meaning. 

"Why does this sentence starts with gone?" --- I believe it does so because: Why does this sentence start[] with “gone?” ))) And probably a little bit because of the famous “Gone With the Wind” movie… Since nobody reads books anymore … (without any fake niceties and verbal webs of politeness)))

No longer exists - Gone

It's just a bit poetic.