This assumes that all 2900 people are on opiods on a full time basis. Not a reasonable assumption.
You are correct. BUT, people on these pills are usually directed to take 1-2 every 4-6 hours as needed, so even if half the people in the town were on it, it wouldn't be a big deal. Now, if 100 people in the town were the only ones on it, then sure, there's a problem. But this is nothing more than bedwetting.
That said, they are indeed dangerous drugs.