Check your settings
http://i.imgur.com/8TEf10C.png
If this changes nothing, means you have only one game that can drop cards

It'll take a while. If you want to do more than 1 at a time, use Archi's steam farm. Keep in mind although that each game you run at the same time multiplies the time by about 2x. So it keeps doubling until you eventually have a stupid amount of time between drops. Or you turn them all off in annoyance and the timer hits 0 instantly, giving you 1 card.

There's a setting under, surprise, settings which allows you to do many at a time for 2 hours, but the dev for idlemaster never got around to multiple-forever as a setting before he discontinued it.

No