Dreamer stopped smoking because:
1. He didn't need it anymore- it was used for healing and it did its job.
2. He had enough experiences for a lifetime during his 50-odd experiments.
3. He did not think further experiences would give further insight.
4. Smoking probably isn't healthy. He is now a health freak because DMT made him realise how precious life is so he wants as much of it as possible.
5. The launch can feel like too much, sometimes too intense due to the rapid propulsion into hyperspace weirdness (this "what the fuck" experience doesn't have to be experienced many times to learn from it), and he wonders if too much such stress is compatible with maintaining optimal health. He now prefers the slower onset of other methods of ingestion, and the regulation of heartbeat etc provided by ayawaska etc.
6. There is no historical precent for smoking lots and lots and lots of DMT to be confidently considered healthy (unlike positive historical use of ayawaska).
7. Terrence got a brain tumour, eek. Note that is not thought of as related but makes Dreamer wary nevertheless.
8. Dreamer's spicemaking skills may not be removing all impurities.
9. It's too short for him now, so he's switched to other methods of ingestion. Fed up of having to leave female entities just when they're getting frisky

10. He is in complete awe of smoked DMT. He respects the experience and even fears it a little.
He will smoke again one day if he ever feels the need, of course. Don't read this as meaning you shouldn't try smoking DMT. You definitely should!