HOA's tend to want their cake and eat it too. But it's a question of what level of dues is the community willing to bear in the name of security. Ideal is security at every gate and roving patrols 24/7, but that's a good chunk added to the budget.
Doesn't work as well up in the mountains where you have huge lots and a ton of land to cover as it does in a golf course community where the houses are packed in nearly on top of one another. Cost impact is typically more than the community will bear.
Problem with the automated gates, as you said, is the big iron jobbies take a bit of time to open and close. Best solution I've seen to that is to double them up. Use the iron gate for security, but right in front of it you put one of the little simple wood arm gates as an anti-piggy-back gate.
When your card is scanned, both gates open. As soon as your car clears the wooden gate, it comes down swiftly and immediately to prevent piggy backing. The iron gate can then take as much time as it needs to shut.
It can still be defeated by someone getting right on your ass to make the sensor think it's one vehicle, but that makes it pretty obvious that someone is trying to bypass the card scan.