The Irish,Scots and to a degree The Welsh don't dress up to celebrate their cultures?
We certainly don't in Ireland. There is really no such thing as a traditional Irish costume though attempts have been made to 'invent' one since the 1880s. The nearest thing you'll get is the Galway shawl or the Kinsale cloak. The hideous, garish costumes worn by Irish dancers from the 1960s onwards are a modern invention. At least since Riverdance toned it down, we don't see as much of them, thank God.
England is the only country in The British Isles that does not really celebrate their culture,heritage and history.
Well now.........actually England is a superb example of a country that has enormous respect for their culture, heritage and history, as you'd have seen for yourself if you'd ever visited England.