AWS will raise limits if you ask. Increasing EC2 instance limits is usually a quick turn around.

Yes, the default limits are there to prevent abuse and runaway misconfigurations. They won't turn down revenue if you confirm it's intentional.

At least for the tests I've done on a small startup recently, they've also implemented some automatic quota increases for EC2. I ran commands that would have (or did) eclipsed my quota, and got an email that my quotas were bumped a few minutes later.