A very good point, but note that KBLB very clearly has already been paying full (and very effective) attention to such additional considerations!
In the PNAS article they note that adjustments to the sequence of the spider silk protein were made to make it more compatible with silkworms. (i.e: that they clearly did not merely insert spider silk protein genes into silkworms).
Another company did insert a spider silk protein gene into a silkworm and was lucky enough to get it expressed where it was included in the silk (after all, some people even win the lottery!). But it was not included into the structure of the silk and did not significantly affect the strength.
I very strongly suspect that KBLB's sequence changes to the protein were an essential part of their success. That kind of full attention to detail is one of the biggest reasons I believe that KBLB will succeed (the other main one being their exclusive rights to the use of zinc fingers in the silkworm).
There are some very unique aspects to this company that the market appears to be failing to appreciate:
Kim has done a number of things exactly right due to being very exceptionally thorough about his investigation AND clearly having an extremely good level of understanding of what's going on (FAR above what is typical for such companies, IMHO): his realizing that the sequence adjustments would be necessary (note that that was NOT done belatedly after getting the gene in and finding that wasn't sufficient, but IN ADVANCE); his decision to switch to the use of zinc fingers as soon as that tool became publicly available and getting exclusive use in the silkworm. (I strongly suspect that he must have been waiting and prepared for the tool to become available and pounced the instant it did. Certainly there are others that are now very deeply regretting not having done so themselves.)
You have to look deeply at this company to fully appreciate just what it has. Some of the best aspects are not evident from a casual inspection. Which, IMHO, is why the market hasn't caught on yet.
Another thing that only becomes evident after close consideration is the talent Kim has for finding ways to accelerate progress: the switch to zinc fingers from the piggyBac is far from the only thing he's done.
The platform worm was a very smart move and saves considerable time: any successful insertions of the silk protein are readily apparent (the only ones with cocoons!) without any testing (and no markers are needed (which might negatively impact the quality of the silk). There are other such measures that I strongly suspect he is using to speed things up, but I have no way of being certain (and don't wish to assist any competition) so I won't mention them.
Also note that KBLB has already created 10 different lines of platform worms (which could yield 50 different heterozygous lines from crosses - which could form useable lines AS IS (without being made homozygous) since there is a proven and economic method of clonal reproduction of silkworms (and yielding the same population size). That, I strongly suspect is a large part of why KBLB did so many insertions in the last round. It appears that KBLB, if successful, will not wind up with merely ONE Gen2 silk but literally, a whole catalog of them!
There is a lot more going on here than is apparent from a cursory inspect (the type most analysts make).
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