some accents like the southern england rural accent, north of scotland accent and the black country accent are in danger of dying out or being diluted(as in the black country accent which is less strong in the young) some blame the media(even though the media has not had much of an affect on accents like geordie and manchester) while others blame peer pressure to adopt less "funny" sounding accents, even though many accents that could be considered funny are still alive and kicking such as merseyside and brummie.

There are quite a few reasons, each of which would not be a danger to the accent but the combination of several or all is.

First of all, people move around, so you get new people in who do not speak the local dialect and who have trouble understanding the local dialect and accent.

Secondly: Radio and TV, now added to by internet, phone and on and on. People hear other versions of English all the time and think it is fun to speak like the people they hear.

The last reason is less strong now than it has been: When you wanted a good job outside your own region, you had to speak a neutral version of English.

These days a regional accent is more accepted but not in all positions.

Some regions have a stronger local dialect, have still fewer people moving in and have more local culture on the radio or think their local accent is more widely accepted, and therefor they do not mind keeping their local accents.

In the past particularly in rural areas people did not move around very much, spending their whole lives living in one village. Now families disperse and move all over the place, often spending just a few years in each place they live before moving on to a new job or for another reason. This process obviously dilutes

local accents considerably

As others have said, it's because people travel more and have access to other accents on TV etc.

I live in rural Hampshire. The parents of the children at the local Primary School are a mixture of local people and professional people who have settled in the village. I noticed that the children (including mine) started talking with a bit of a Hampshire twang in their early years at school. As they have grown older, it's completely disappeared. Some of them have parents with local accents but now sound like BBC news readers!

I do believe accents are less pronounced nowadays. I found that people from Cradley Heath (black country) quite hard to understand at one time but not so much now. They used words like "howbeest" or "howbinya" for how are you for example.

Kids learn language from television and movies, and most accents aren't heard there. I notice it a lot in the USA.

ACCENTS change with time...Look at old films and tv...