I don't dispute the benefits they could have from using DX11. Obviously, some people developed it because it would actually be good enough for other people to use
What i dispute is that the overall gains (overall as in not only about performance, but general viability of the product) would be so significant to justify an extra few months of delays while they are reworking all of their 3d models.
I mean, if it's already in the engine and it's just turned off because it needs further debugging (as stated on the other thread by one of the devs), then there's nothing stopping them from selling a game in a working state and debugging while the cash comes in, maybe even hiring a few extra people to help do it faster now that they are going to finally start getting paid for their work. In fact, i think it's preferable that not having it for an extra who knows how many months and jeopardizing the entire product's financial viability.
Would it be nice to have it? Well, i don't have a DX11 capable GPU and i don't personally care either way, but sure it would for the people that do. However, i don't think it's going to come back and bite them.
In general, it's a fine balance to release something that works acceptably well right out the box. I equally dislike the practice of companies releasing unfinished games and basing further support and development on initial sales, as i also dislike delaying it ad nauseum to incorporate every new bit of emergent technology, so from where i'm standing they made a well balanced choice.
They left out a half-finished feature that only a minority of the PC demographic can use today, with the aim of working on and completing it during the following months as the amount of people who can use it grows and it would make more sense to include it, while making sure they can release something that will work acceptably for the majority.
All in all, technical specs mean little to me if the feel is not correct and the immersion is missing. This is supposed to be our private little time machine back to the summer of 1940. Sure, graphics play a big part but so does sound and the actual gameplay mechanics and experience in equal measure. It's a compromise between all these things and the capabilities of current hardware.
For example, i wouldn't want it shipped with DX11 if that meant having to axe other features like the new multiplayer modes, the multi-level AI routines or stuff that have to do with the actual flying. It's a game about aircraft first and foremost, so as long as the aircraft look accurate and fly close enough to the real thing i'm not going to mind having a few less polygons for the sake of playability.
In any case, this is my personal opinion and not some kind of gospel to be forced on you so by all means feel free to disagree. It just seems that the majority of potential customers are more interested in having the sum of its parts capture the "time machine" feeling, instead of having one part being excellent to the detriment of the combined total