You are right. The vendor prefixes are there to introduce new properties that they hope will be implemented in the standard. All those prefixes can change or disappear altogether and without notice.
However, this is a way for a browser vendor to test their code in real life. If it fails, they can change the prefix and try again till they get it right. You can't do that once it's standardized. In fact, there are a number of properties that have been implemented incorrectly and still exist today but were eventually fixed in the non-prefixed property.
But a developer is to then remove the prefixed property. Not complain about it and blame others for their decision to use it in the first place.
The Web was certainly working before that functionality, which should be considered beta feature anyways, and you could've waited till it was standardised. If we'll support each and every lousy developer on the world, things will surely get more complex and dirty. And no user will ditch a browser for some css not working, they'll use the other browser temporarily for that website. Throughout this thread people consider users as lousy, nagging, complaining, brain dead people that jump from one browser to another, but this is not the case. They're as smart as each and every dev here, they just don't know programming. I guess what's going on is that devs and amateurs make lousy stuff and go singig the song of the infedele users because they don't want to fix their things.
Not exactly, as the functionality is experimental and subject to change. That was the whole point of the prefixes.
Syntax and behavior of css changed between proposals and early drafts of a new feature and the final result.
So without prefixes you'd have a single "XXX" CSS name that might get deprecated altogether (eg the name ends up XXY) or be defined to have different behavior (e.g. it remains XXX, but not it also makes the element bold rather than just italic).
However, this is a way for a browser vendor to test their code in real life. If it fails, they can change the prefix and try again till they get it right. You can't do that once it's standardized. In fact, there are a number of properties that have been implemented incorrectly and still exist today but were eventually fixed in the non-prefixed property.
But a developer is to then remove the prefixed property. Not complain about it and blame others for their decision to use it in the first place.