Let's talk about what's actually happening neurologically at 40, 50, 60+.
Your dopamine system has naturally downregulated with age. Baseline dopamine activity declines gradually with age. This means the highs are lower — but it also means the contrast between dopamine-hit and baseline is sharper. You feel the crash harder than a younger person would.
The prefrontal cortex, however, is at its strongest. The part of your brain responsible for judgment, impulse control, and long-term thinking is fully mature and more practiced than it's ever been. You have more self-regulation capacity now than you did at 25 — even if the habit makes it feel otherwise.
Recovery at your age is different, not harder. The withdrawal may feel less dramatic because your overall dopamine system is calmer. The discipline may come more naturally because your prefrontal cortex is well-practiced. What's harder is the psychological weight of "I've been doing this for decades." But that weight is a feeling, not a fact about your capacity to change.
Your prefrontal cortex is stronger than ever. Recovery at this age is different, not harder.
Think of one difficult thing you've overcome in your life that took sustained effort. You already have the discipline. This is the same muscle.