Any recovering addict worth asking will tell you they have not forgotten how to get high. They will probably also add that they never stopped enjoying the high, it's the consequences that they couldn't stand.
The experience of addiction is never forgotten. Not just the high but the whole behavioral practice leading up to the high. Ask any addict what it's like to cop. From the drug infested neighborhoods to the sound of a dispensing ATM machine, it's visceral.
Scientists have documented dopamine levels increase in anticipation of the reward. That endorphin increase connects the preceding activity to the hit. All of it, the coping and actual ingestion of the substance reinforce and connect you to the experience.
If the drugs don't get you the lifestyle will. That's why it's not enough to simply stop using drugs. One has to actively work on changing their attitude and behavior in order to stay stopped. The deer that wanders onto the road at night receives two competing signals, one to stop and one to go that freeze him in the headlights and bring it's life to an abrupt halt. Recovering people specifically those who use the 12-Steps figured that out a long time ago. Their approach, going to meetings regularly, doing step work, sponsorship, and service is designed to help one make the lifestyle changes necessary to avoid getting run over by the disease of addiction. There's always two parts to any behavior change one wants to make, cognitive and behavioral.
The opposite of addiction is not recovery it's connection. You never forget how to get high. Once you learn how to swim, you may not swim for years, but once back in water you will instantly remember. You could take any recovering person and drop them off in any city in the US and they could cop dope within two hours. As a recovering person myself I can tell you I know where to find street drugs. The only reason I'm not high right now is because I have some connections I don't want to lose. Whether it's my partner, my job, my kids, my grandson, or god children I don't want to give them up. Connections are the key.