Blyth, Bedlington, Ashington , Newcastle and Morpeth all had very distinctive accents, I always thought it was because of their local industries, farming, mining, ship building and ports and the fact that there was a very little amount of travel in the OLD days.
Travel, media and the economy has changed all that and the dialects and accents are all being diluted, is it better or worse? who knows but I see such as the u-tube videos are doing a great service preserving it for the future, I wonder if museums are archiving some of it!