PostNord already did this in Denmark, to the extreme, which render their services pretty useless. Letters will frequently take up to 10 days to arrive.
A previously employer resorted to ask staff to take mail with them as they traveled between locations and drop of letters to clients when they either visited or drove past anyway.
Some government services didn't take the hint and mailed papers for signing, asking for them to be mailed back within 14 days, but if the letters doesn't arrive until 10 days later, how are you suppose to have it returned within 14?
Danes don't send much mail anyway, but the reduction of service just made everything worse. You can barely rely on PostNord for Christmas cards without posting them before December.
Their package delivery service is excellent though, but only in certain parts of the country.