Quote - There is a behaviour that I do not understand and that makes me mad: people being told no and... repeating the same question as if the response might change.

Because it works...sometimes.  DAZ has given in to customer pressure before, if it was loud enough and persistant enough.  Not always, but such intermittent reinforcement produces behavior that is extremely difficult to extinguish.  :-)

And it's important to me.  Maybe it's trivial to others, but those installers pretty much drove me from Poserdom for a couple of years.  Poser...7 or 8?...I don't remember which one, but it didn't get along with V4 and her sisters (Aiko, Girl4, etc.).  I couldn't even install them.  They wanted to be in the main runtime, and they wanted to be in the same runtime.  I don't put anything in the main runtime, and I have separate external runtimes for each figure.  I was used to moving the !DAZ folder to the main runtime to get it to work, but the V4 generation installers were a nightmare.  I was moving CR2s, copying OBJs, editing INI files, trying to get it to work, but it didn't. 

This is a hobby for me.  It's supposed to be fun.  That wasn't fun.  It was time to get a new hobby.  I still kept my PC membership, but a lot of vouchers went unused.  (Didn't save me any money, though.  My new hobby was photography, and I ended up spending thousands of dollars on pro camera gear and software - money that had been sucked into Poser content before. ;-)  I came back when Poser 9 was released, and found most of the installer problems were fixed, in that they actually run.  But they're more obnoxious than ever. 

Please, DAZ, look at how Cornucopia3D does it.  They have newbies using the free version of Vue and pros who spent thousands on the pro versions.  You can choose between installer or zip, for each file or globally.  You can even download one of each, if you want.  It works well to meet everyone's needs in that very diverse customer base.