I was surprised to learn how far back this "holding holidays on Mondays" went, because I don't recall it from when I was a student. I needed to go to the bank this past Monday, didn't occur to me the bank would be closed. No mail either. Is it accurate to assume New Years Day (this coming Sunday) means next Monday will be yet another federal/legal holiday?
A lot of business's were closed on the Monday after Christmas, but a number of those business's will be open the Monday after New Year's Day. However, no mail delivery and government offices are closed. There are certain "government" holidays during the year that small businesses, and some large businesses, don't observe. When my wife worked in the banking industry, she got Veteran's Day off, but she doesn't get that day off now working in the insurance industry.
I think that if a holiday falls on a weekend, workers are required to have a Monday or Friday off. In the past, employers did not have to give workers a day off if the holiday was on a weekend.
Again, can depend on the company, even if it's a government/federal holiday. Martin Luther King Day is a federal holiday, but for some companies, it's not a holiday no matter what day it falls on. I never/ever got Veteran's Day off.