Like you, I have been critical. However I think Yaohan's two statements from Devialet on
https://help.devialet.com/entries/24093291 go a long way towards acknowledging that they did not get 6.0.6 and/or 2.0 right and they should have acknowledged that earlier. Don't be too critical about the wording he uses as I doubt English is Yaohan's first language.
What appears to change between 1.5 and 2.0 seems very fundamental (and I had no idea about this) with more reliance on realtime and less on buffering. So I guess they cannot review these developments by looking back and moving to how they did it before; nor can they look at competitors because no one else does it this way (as far as I know).
I know from direct correspondence with Devialet that they know they got it wrong - probably through lack of time - in relation to 6.0.6 and/or 2.0; in relation to the new website; and in relation to not acknowledging the dropout problem earlier. I guess the timing of Munich was not ideal and they would have had to take a decision whether or not to launch there - at what is the most important non-USA show and arguably the most important show for them in the world.
Let's remember that they have got lots of things right: the most innovative product for a generation; fantastic sound quality; great flexibility and tailoring for inputs and outputs; free future firmwares; well positioned new models; and what looks like a fantastic offer if you want to move from D-Premier to 240 (which you don't have to do, of course).
As an earlier poster explained, there is a beta version of a revised 6.0.6 and a revised 2.0, now at beta2 stage I understand; and i bet Devialet teams are working all hours to get this right. It would be unreasonable to expect them to put a precise delivery time on this and better for them to say "as soon as possible". Similarly, updates in relation to progress on beta testing have questionable value since customers will only be interested when it is fully fixed.
I don't criticise them for releasing the new models - these will work with all conventional inputs and with a computer via digital outputs or with ethernet or USB.
An important redeeming issue is that the people I have met at Devialet seem straightforward, committed and expert in what they do so I think existing and potential customers can be reassured.