Why shouldn't different members of society be encouraged to mix?

After reading an article on the Guardian website recently, this got me thinking, why is there such a divide between generations in the UK?

At present, different generations are separated into different sectors of society based on their interests, most of which are rather stereotypical. For example, most teenagers & young people are only interested in alcohol, fashion, the internet & gaming. Whilst the elderly are associated with classical music, quiz shows, period dramas & theatre productions. But is this really the case? Or are these stereotypes outdated?

It seems that for anyone under the age of 21 to like or listen to music from before their time is frowned upon, as is people of slightly older generations liking chart music, but who decided this wasn't allowed? This diversity in likes & dislikes must be good for relations & stereotypes yet it is always seen as being an odd thing.

Even with social places like pubs, it would seem people are divided, with some places being 'student pubs', some being for working class males, some catering to families & those seen to be for older people. Each generation looking down on the other with their own stereotypical views which are often based on media perception & past experiences. Although if all generations were encouraged to mix, I believe it would have a positive affect on society. 

I think that everyone has something to offer in terms of knowledge & opinions, different age groups could teach others so much about their interests & life experiences. Many older people will have good stories to tell of a time before technology as we know it today, whilst young people can share their knowledge of this technology. 

By encouraging this kind of togetherness, stereotypical views of certain groups could be changed or removed within society. Making the place a lot nicer, changing peoples perceptions should be something we're promoting, especially at times of recession, as many people will remember previous times of economic difficulty & be able to share tips on how they coped in the past. And after all, with all this doom & gloom, some new friendships & trust between communities can only be a good thing!