The rates are adjustable in the game settings menu, and it breaks down between The Repeater and Everything else, haha. The Repeater is the one that you start with. Currently, it is infinite and shoots slower because faster rates make the game even easier. Slower rates make the beginning of the game a crawl though.
You didn't miss anything, but some of the buildings do have limits (I believe around 500). It's a hold over from when everything had a stocked inventory of balls...but I also like how it limits things. It is not conveyed to the user at all but in the settings, you can turn on this display. I have it off by default because it clutters up the screen so badly. I'm thinking of ways to show it without ruining the clean look of the game right now.