Anabolic and catabolic hormones are not the only factors. You have muscle memory too
https://www.ncbi.nlm.nih.gov/pubmed/24167222
You can very well retain muscle gained from AAS use, I have plenty of friends I have known for years who have proven this.
Sounds like you are saving time and taking shortcuts

The number of possible variations in training methods is large, and you'd have to both read some scientific literature and try out for yourself. Due to weight training being a novel stimuli the first year, you may very well be lead to believe that what you are doing is whats best for you, and have the potential to get better but think this is your limit.
I know for example my results now are sub optimal because I don't have the time to perfect my diet and rest. I eat IIFYM because I work 80+ hours per week. I have experienced better gains with better meal timing.