The problem is that guys equate the look of steroids to muscle.
Steroids increase nitrogen retention, glycogen uptake, and intra muscular water retention...All of this adds to that round, hard look that you get from drugs (even testosterone).
When guys come off, or even go down to TRT from hefty doses, they lose that, but they haven't lost the muscle itself. Just a big portion of what composes it.
Anyone whose gone on TRT from years of gear use will tell you, sure they aren't their strongest, but they aren't THAT much weaker than when they were off (neurological adaptations to high load have already taken place in a way).
Now coming off completely is a personal decision and TRT is still a big advantage over this, but the minute the drugs are added back, you'll gain back that look pretty fast.
How much you hold is up to your training, diet, genetic limit, years spent training naturally...