When the Baby Boomers were growing up, a half-hour show was actually 22 minutes long. That’s about 27% commercials, although it didn’t always seem like that much because some of the commercials were commercials for other shows.
From the 40s to the 60s programs had sponsors and the cast would even pitch the product sometimes within the program and sometimes adjacent to commercial spots. So they were ads but they were also part of the program