There are still occasions for semi-formal day wear, and Easter Sunday in a large city can be one of them. The others are weddings, some diplomatic functions and the occasional funeral.
I think a black jacket and checked trousers are among the most attractive things a man can wear. Unfortunately, in an age when the American President-elect doesn't dress formally for his inauguration, formal and semi-formal day wear is usually seen only on hotel managers and the customer-facing staff of very old-fashioned English banks.
Oh well. Spring is in the air. Happy Easter!