Old News I just ran across
So, spider silk is even capable of something like this; which means I'd say that all dridders have probably just acquired another useful ability.
Dridder society I think is one of those many things that is discussed at a level where people forget their natural unique ability. For example, I'd almost certainly think that you'd see the dridder society building homes out of silk, vice, y'know, actual buildings; given the structural property and comparisons. If they needed something more fortified (though it is extremely difficult to argue with the tensile strength of their silk) I could see some of them taking up residence in locations that had been built by others and/or using underground caverns, but I think a good reason their society doesn't have ruins is that most of the former silk constructs have decayed away without tenants to provide upkeep.
Moreover though, such items provides the smaller dridder inhabitants of the Matomo Docks with a very unique selling point - them being weavers and clothiers has almost always been presumed, but if their silk is capable of such things as oxygen exchange in water I imagine one could easily see medicinal uses as well as construction (they make rather handy cranes, even the small ones - would just require load balancing and a secondary 'tower' object in their case), water treatment, et cetera.
I post this in the Dridder section since this in particular applies to Dridders, but actually my intent was to look at Negav's technology base again. Negav is definitely a society that encourages 'capitalism' and I think the reason for the 'allowance' of areas that promote non-human living quarters is probably more related to the beneficial aspects that small predator species can provide without technology or magic. Technology has always been one of the stumbling blocks for describing Negav, but I think we could describe a lot of the interrelations and society intermingling with the benefits and detriments the non-human species offer. Besides ironing out the trade/ability that dridders offer, we ought to look at the other species as well. For example I've already looked over slimoids and come up with a variety of ways their unique species traits could be used to supplement or outright replace technology in the city's environment.