A difference here is that Frontiers Developments are Europe based and bound by the consumer protections there. Things that cannot be signed away or over ridden by what KS saying in their terms.
They made a number of unambiguous statements that the mode would be available and these are almost certainly binding. Such as this 1 week before the KS closed.
That is strong grounds for a refund and they really do not want to get the consumer protection regulators involved, or generate bad will for release day reviews. The KS may have funded development, but additional sales are needed to keep the servers running and review score will decide if that happens since it is not planned to be a subscription game.
The game looks great but I will still be surprised if they are in the very small % of server based games that still have their servers online a couple of years later.