Larian is aware of that fact. Part of the delay was unavoidable, and part there were other factors involved that made the chosen path the best option overall, despite the disadvantages.
The price for D:OS hasn't dropped that significantly; the last Steam and GOG sale it was 33% off. When the Enhanced Edition is released some people may want to wait for a discount they figure is appropriate for the age of D:OS, but that is not exclusive to Linux (just more of a potential issue since there is no Linux version of D:OS).