Back in the day, people would buy graphics libraries to draw lines on the screen, buy utilities such as ZIP or defragmentation utilities, and each program had its own logic for printing, with each of them, at setup time, asking questions such as “what should I sent to you printer to get bold text?”, “how many characters on a line does your printer support?”, and “should I wait a bit longer between lines to make sure your printer is ready to accept new input?”
Now, of course, Apple doesn’t need to make money on their OS, but I think they are forced to move ‘up’ to compete with Microsoft.
I remember I coded a spell checker for WordPerfect 5.1 after I used Word and wanted to have the same.
Sadly the 40MB hard disk where it was died many years ago.