"Though their fiber is more coarse and uncomfortable"
when you take into consideration that their partners and financiers are in the auto parts business, i cant imagine why spiber would need to be concerned with the softness or comfort of their silk...it is obviously being produced for auto parts and car manufacturers...
bolt threads would need to be concerned with softness and comfort...and they recieved $40 mil to commercialize their product...
something tells me bolt threads silk not coarse or uncomfortable...and I suspect spiber could produce their silk softer and more comfortable...they just dont need to... it might not even be a good thing for what they are using it for...