Believe the mark of the beast has already occurred decades ago. No one without the mark can buy or sell without the mark. Buy or sell means do business, not an individual going to the store to buy something. The little guys, the mom & pops were put out of business long ago by the big chains. The big chains have the mark. The inventors, who came up with a new mouse trap did not have customers beating a path to his door.
The mark is either on the back of the hand or the forehead. The mark on the hand is a metaphor for one's actions. The mark on the forehead is a metaphor for ones plans and schemes, often provided in writing. Like a manifesto or technical paper.