By all means continue to think that it is easy to stop smoking (no-one disputes that it is possible; the relevant point is whether it is easy, as I hoped was clear from the start), but as is often the way, the second paragraph of the Wikipedia page contains the appropriate information. Of all attempts to stop smoking without assistance, between 3 and 6 percent are successful (though the article later suggests an average 7.3% success rate).

Stopping with chemical assistance, the success rate rises to about 30%.

https://en.wikipedia.org/wiki/Smoking_cessation