To the exclusion of reality? Never. Nor would I say the customer is never right, or doesn't generally have a point, even if I try to explain the reasoning behind something, etc.

There may be game companies with effectively unlimited resources that can take as much time as needed for the game and be able to do a thorough QA period after everything is balanced and finalized. That is certainly the ideal situation, but very few companies have that luxury (and a couple who did took so long they ended up with an obsolete game by the time they were done, and had to go back and update the game engine, which of course adds more development time and potential for bugs).
Any finite QA team is also not going to come across every rare bug or think of every possible exploit that the full player base will eventually come up with.

Given finite resources, there must be a release at some point. If there is a retail release, the date is set in advance based on estimates; at some point that becomes very difficult to change, even if something unexpected happens or things take longer than predicted. That's why day one patches are very common.

With a development time shorter than what would be ideal, which is almost always the case, there is a trade-off between development time and QA. Larian's approach is to be ambitious with design and develop as long as possible. As described in one of the older blog posts, a fun game with bugs can be patched, but stopping development too early can result in a minimum of bugs, but the game not being fun, which is much harder to fix.
A similar situation affected Beyond Divinity, actually. The ending of Divine Divinity was rushed when the publisher set the release date, and much of the content cut (so it was mostly just hack and slash). To prevent that from happening with BD the ending of the game was done first, but that resulted in the rest of the game always erring on the side of caution with design, so as not to risk having to redo some or all of the ending. It is still a good game, though.

With D:OS, the release was delayed multiple times, literally as long as it could be delayed (fortunately the investors and retail distributors that had signed contacts saw the value in more development time). Larian deferred paying taxes, then got caught when the government changed the regulations for that, took out loans to pay off other loans from banks that were getting nervous with the delays, then took out another loan shortly before release to add some voiced lines (from someone IIRC described as the last banker that would still talk to Larian).
The Enhanced Edition took longer than projected. Originally the plan was to release all platforms simultaneously, starting with QA on the console versions (given their extra approval process with both Focus and Sony/Microsoft), then Windows and the Mac and Linux ports, but only Windows was (barely) done in time for the release date, and OSX and Linux followed some time later.

D:OS 2 will not have a retail release on PC. While there are presumably multiple reasons for that (for D:OS, the retail release took up a lot time near the end of development, when the game was still being worked on), this will result in the release date being more flexible, with no contracts or manufacturing and retail deadlines to force a release if there are issues late in development.
There are no other platforms announced for D:OS 2. If there will be console releases, delaying until after the Windows version is out, and any issues fixed, will avoid most of the issues with the much more involved update process on console (the initial approval process would presumably not have to deal with any general gameplay issues, and only platform specific issues, if present, would need to be fixed).