Yes, I didn't leave my son until 3.5 with no opportunities to learn, like pp I 'tried' a few times over the course of a year or so.
Early tries very rapidly descended into screaming, upset, fear, hitting and pleading, within the first couple of days. Trying very hard to do it, but wetting indiscriminately, and getting extremely distressed by it. Couldn't manage his clothes at all.
When he was finally ready, yes it still took 'work' to iron out a few difficulties (still does..) and reminders etc, but he could do it. A few tears and anxieties and mishaps, but actually making progress and gaining confidence. Can now handle the undressing and dressing side of things.
I did nothing differently each time, and nothing different to what is suggested on countless potty training threads.
Why would this be different to any other phase of a child's development? They don't all do things at the same time. You wouldn't say a child with any other development issue had lazy parents. They go at their own pace, as is right.