People have always believed things were better in the past. I vaguely remember some Roman writer (Horace?) noting that every generation complains about declining morals.
That said, I do think things have changed. And it's partly down to the end of the class system. When I was young (in the 1970s), this country was still twisted up by class. Just watch any British sitcom pre-1990. It's almost always to do with class. Well the class system was a pretty toxic thing. It kept people in their place, and held Britain back in lots of ways. But it did have one upside. Because people were frightened of being thought 'common' or 'lower class' they would teach their children an elaborate code of manners.
I'm not talking about the upper classes by the way. The aristocratic/Bullingdon type are often incredibly rude. You only have to look at the royals. It's hard to imagine anyone less refined or polite than Prince Philip, not to mention that ignorant little oaf Harry. I'm talking about ordinary working people in the suburbs. If I went to another child's house for dinner, for example, I would have to say "thankyou for having me," when I left. And I even remember my grandfather grabbing my little brother, yanking him off the pavement, and saying "you should always step into the road if a lady is coming"!!
There were two words I often heard as a child but never do anymore. The first was 'gentleman', the second was 'common'. You'd hear older people say of X or Y that he was "a true English gentleman," or "an English gentleman to his finger tips". You also heard people describe neighbors as 'common', or even 'vulgar'. That kind of language just isn't used anymore. I cannot remember the last time I heard someone described as 'common'.
Ironically, it wasn't a Labour government that destroyed the class system. It was Thatcher. Thatcher made everything about money. People increasingly judged one another not on their 'class' (their manners, taste, accent, cultural interests, etc) but on their wealth.