Back in the day, when you buy a product and pay the company for it, the deal is done. The company would have made its money from you and that was that until you purchased from them again. However, it’s not particularly sustainable as companies would essentially need to keep courting buyers.
This also means that during particular times of the year, revenue could be down. This is why we’re seeing an uptick in subscription services that at least guarantees that existing customers continue generating revenue for companies, even if they aren’t necessarily buying new products. This is the case with Toyota who are now charging customers $8 a month in order to keep using their key fobs for remote start.