I'm all about teaching the kids about their history, and that goes for video games too. Usually, if you ask someone over the age of 30 about video games, their first experience was either with Pac Man or Galaga. Those were two of the biggest arcade hits ever, and just a smaller does of what made Namco a household name among gamers with good taste.
Namco was started 1955 under a different name (Nakamura Manufacturing), and they operated children's amusement rides on the roof of a Tokyo department store. As time went on, Nakamura Manufacturing Co. (which Namco is an acronym for), decided to enter a new realm of amusement, arcade video games. In the 1970s, Namco purchased Atari's Japanese arm and became the sole licensee of Atari arcade games in Japan. They didn't start making their own games however until the 1978 game Gee Bee. they followed that up with Galaxian in 1979, and what many consider the greatest video game ever made, Pac Man. After that, Namco hits their stride with a number of classic arcade offerings. between1980 and 1982 Namco released Rally X, Galaga, Ms. Pac Man, Dig Dug, Bosconian, and Pole Position. That list alone is enough to cement any game publisher's legacy, but to see them all release in such a short span from one publisher is the stuff of legend in the game industry.
The mid to late 80s saw Namco continue to innovate in the arcade and home markets, but their streak of classic games seemed to have calmed a bit. While they released games like Mappy, Sky Kid(kinda obscure, but worth the effort to try it out), and Pacmania (My favorite Pac Man game), the output prior to the crash of 1983 just wasn't there anymore. This may be more due to caution on the part of Namco being cautious about the prospects of another crash looming.
The 90s saw Namco step back into an innovator role, being one of the first arcade publishers to venture into the polygonal graphics. Games like Starblade reintroduced the gaming community to the Namco that made a little yellow circle an icon, while Time Crisis, Ridge Racer, Tekken, and Soul Edge/Calibur solidified them as a top player in the arcade and home marketplace. The last decade seemed to not be as good to Namco as the last 2, and because they weren't so eager to jump onto current day fads, Namco's sale slumped, but nostalgia can keep a publisher with a great back catalog in business any day. So, Namco began to revive some of their older franchises, and games like the Pac Man World series grew in popularity. Meanwhile games like Mr. Driller, which most gamers saw as a spiritual successor to Dig Dug, continued to get sequels and spin offs. recently, with arcades nearly extinct in the U.S., Namco has merged with Bandai and their classic catalog has slowly began to evolve with the times. For example, Pac Man: Championship edition and CE:DX have both been considered the best games released on XBLA in a long time, which continues Namco's tradition of making it tough for other game publishers to follow suit.
Namco's arcade legacy is probably richer than most publishers, but it was never truly about the number of games they released, but about the dedication to introducing something new and fresh to the marketplace with each cabinet they released. Namco in some respects were the standard bearers for arcades, and in some cases, they raised the bar too high to reach it themselves.