It does happen. Getting a full dose of fresh fuel is huge. I deal with a buttload of small engines on farm equipment. They sit idle for 9 months. They are a pain to fire up after sitting. After about 20 minutes of high rpm running, most settle in nicely. Dome still need a deep carb cleaning..
Agreed, the more they run with fresh fuel and fluids...the better they seem to get. Fine tune from there with maintanance and they tend to get even better. These old cars don’t like to sit.