You were probably just venting for the sake of it, but you can't blame coaches for waiting until the last second to renew, because that's when they get credits to make buying the next team cheaper. Especially coaches who get bounced in the first few rounds of the NT, days go by without checking your team and you just don't think about it. Then you only have one day to renew.
Maybe you would like to suggest the following; credit all the coaches on the day they lose, so that they can renew right away with their discount instead of waiting to do everyone together.
This would probably make it easier for coaches from forgetting to renew, which I agree seems to happen a lot.