The longest period of time I've ever had heroin seem to last is about 12 hours or so. After which I almost immediately start experiencing withdrawal. But yes, heroins considered pretty short acting. Like oxycodone and morphine and such. As opposed to long acting opioids like methadone or oxycodone extended release and others.
As for withdrawal, I've certainly experienced opioid withdrawal god only knows how many times, and I hate it so no way would I subject myself to it on purpose. As for "you shouldn't do opiates then", bit late for that now...
I'm not sure how old you are, but both methadone and narcan have been around for about 40 years. So I'm surprised to hear you say it wasn't around "in your day", whenever that was. Though obviously it would have shown up in some regions later than others.
Sorry but I don't buy for a moment that it encourages drug abuse more than before though. I think that's total bullshit. Nobody starts heroin thinking "oh its OK if I get addicted, I'll just go on methadone!". And I doubt almost anyone thinks "oh it's OK if I use too much, there's a pretty good chance I won't die and will just wake up in hospital with horrendous withdrawal!" either.
Sounds like crap to me. Sounds like one of those things people just make up based off nothing.
Sorry if I sound a bit hostile here. It's just that we have enough naysayers putting peoples lives at risk with completely unfounded hypothetical reasons to object to maintainence therapy and ready access to naloxone for drug users as it is without other drug users suggesting it.