Trouble is, doing it 'live' is destroying the reputation of the game. The amount of goodwill burnt is akin to this
My guess is that FD need these updates to the renderer for other games.
certainly, one shouldn't do this live - but they are in a bad position already, if they are waiting too long to show something significant, they will loose even more players, who are giving up on the idea that FDev will be able to do it. And if they show something and it isn't working properly, that has a similar effect - but at least it is showing that they are actually doing something in the right direction. Otherwise people might start to think, all talk but no action.
The proper way would have been to state - we made a mistake, we seriously believed it would be ready, but we see now it just isn't - so we offer a refund for anyone who wants one and put it in early access state - so if you are playing it and it works for you, you can play on, the others can get a refund and buy it at a later time, when it will be done. It can take a while, because we need to redesign major parts of the rendering engine and our planetary generator - this would be honest and honorable.
I really doubt that a lot would actually request a refund, if they would offer it, admitting failure like I outlined above showing as well what kind of work it is, what has to be done. This would be fair towards their customers and towards their staff, which is currently under pressure and pressure is not a good motivator for well done innovative work If they would have done it like outlined above, they would have taken the pressure off their staff and raise goodwill among their customers again - people are paying for early access games, so not that many will actually go for a refund - one just has to be bold enough to be honest, straight forward admit failure and be fair to customers, who can't play the game by offering a refund,