Quoted from Mr68:
In the 70's? It was Williams, Bally, Gottlieb, Stern, and Atari. Capcom was 90's. Who am I missing?
And 7 titles a month? Really?
edit/add: Forgot about Game Plan but they only made about a dozen games in total.
I just picked a year at random and looked at '77. Manufacturers who made a game that year: Allied Leisure, Gottlieb, Bally, Zaccaria, Chicago Coin/Stern, Williams, Sonic, Sega, Recel, Playmatic, Atari, Segasa, Interflip, Nordamatic, and a few other home pin makers and smaller manufacturers.
Here are the number of games that came out each month starting in Jan.: 2,9,4,10,6,10,6,6,8,5,8,6 plus there are 39 games listed that don't specify a month for a total of 119 games in the year which averages 9.9 games a month. If you don't count the 39 games, the average is 6.67 games a month.
Sorry I love numbers. Most people think the golden age was the 90s but the 70s was the time to be making pins and putting them on route. I'd love to hear the numbers of what operators were making in those days compared to other time periods.
This bubble burst sometime in '82 or '83. '82 was the last year for a game to sell 10k units for this time period. Atari and Stern went out of business and probably some others I don't know about. Bally and Gottlieb changed their names to Bally Midway and Mylstar signifying a merger or buyout maybe. '83 averaged about 3 new games a month.