> Your razor does try to stop you from using a blade from a different manufacturer Not very successfully. > your printer tries to stop you from using ink cart

> Your razor does try to stop you from using a blade from a different manufacturer Not very successfully. > your printer tries to stop you from using ink cartridges from a different manufacturer I can inject ink into the port, for cheap. > your car will often strongly discourage you from getting it serviced by anyone other than an authorized dealer. Only the top-range cars, for rich and upper-middle-class people, who have the ability to buy different but won't because it's a silly status symbol.