As a fan of old movies (I mean, films) I've really tried to find out what killed off "swell" suddenly around 1947. Overused in the early 40's and extinct by 1950.
I thought swell had come into use around 1930, but I spotted "swell" on a silent movie title card from the early 20s.
I'm giving up on trying to save the word "Problem." It's now been completely replaced by "Issue."
Final straw was hearing an airline pilot on TV a few months ago refer to an engine fire at 30,000 feet as "an issue."
"Groovy" went? No Way.