Why do most people think new Northern line is gonna kill the X20/X21/X22

You have LNER going to Morpeth/Alnmouth & Berwick but you don't see the X14/X15/X16/X18 losing passages do you.

This new Northern Line will not take passengers of the X20/X21/X22 cause the line doesn't even stay with them. The line if I'm right doesn't see them routes till Ashington and even then the X20 is the only service that does Newcastle to Regent Centre then non stop to just outside Ashington. The Northern line is to connect villages that have 1 or 2 bus services and to run a services. Not to take passenger of a bus route