When I was a kid, there was Mothers' Day. The others were never heard of. Then Fathers' Day came along with its vision of tinkling cash registers, and it has stayed.
Valentine's Day took a lot longer but commercialism won out, and there went more flipping great wodges of cash.
Next, of course, came Halloween which we had to have because the Yanks did, and kids saw it on TV and that took care of that. More currency escaped into shops with (expensive) costumes, and from householders who thought that that "Trick or Treat" really meant Treat. (Note: A hand-held foghorn is a useful Trick).
I imagine that some enterprising sod somewhere is now working on a way to make a dollar or three out of St Swithin's Day (gloom).
"We'll all be rooned" (said Hanrahan).