Just like booze, so what's your point. I don't get why it keeps being repeated?
Right, alcohol also exhibits similar properties of tolerance and escalating "doses." BTW, nobody here is suggesting that alcohol-related death is not
also a major societal health problem. It's not "either/or."
You are verifiably correct as to tolerance...what is missing in the studies is the conclusion that tolerance will inevitably lead to overdose. There are a plethora of studies (I found over a dozen using your “tolerance” search term) addressing tolerance, I could find none supporting the trajectory to overdose and death.
Obviously, I am giving your hypothesis that ultimately tolerance leads to overdose and death full credence; that I have not found such a report is the reason I am asking you (or anyone else) to provide such.
Thanks. Since you seem to be interested in exploring this, it's actually a little more complicated.
Like other opioids (and similar to alcohol, as Sal1950 points out), tolerance leads to escalating heroin doses. But tolerance to the euphoric effects develops sooner than tolerance to the respiratory depressant effects. At these higher doses, when the abuser then happens to concurrently consume other drugs (like alcohol, benzodiazepines, etc.) that are also respiratory depressants, the result is additive/synergistic respiratory depression, which can become a life-threatening or fatal event. This is why when heroin "overdose" deaths are examined, it is common to see polypharmacy on the toxicology, along with the heroin "blood levels" that are not elevated beyond the elevation expected by a chronic heroin user.
In other words, it's not the heroin itself causing the overdose, but rather the baseline respiratory depression caused by the higher doses of heroin (a result of tolerance and the abuser's need to maintain the same level of euphoria), which creates a situation where adding alcohol, benzodiazepines, etc. can result in death.
As mentioned, you can't directly study how heroin abusers eventually die because of issues of ethics (you can't just watch someone die in the name of science!) and issues of access (heroin abusers don't like to be followed around by people where lab coats). That and if you follow the money, who will fund such a study? (certainly not big pharma, which likely caused the opioid epidemic in the first place)