I don't find silver to sound thin or lack bass. Almost every time I've put a silver cable/connector into my system, I've heard what I consider to be an improvement in clarity AND smoothness, as well as improvement in bass. The only place I like all copper is for the power cables for my class D monoblocks.
I build my own cords, though, and can use whatever gauge of wire i choose. My ICs are built with 24 gauge solid silver.. my guess is that those who find bass to be weak with silver may just be using cables that have smaller diameter conductors. This can be the case since silver is more expensive and has slightly better conductive properties, so cable companies could be using thinner wires to make the cables, reasoning that the better conductivity of silver will make up for a higher gauge relative to copper. But it doesn't.
I build my own cords, though, and can use whatever gauge of wire i choose. My ICs are built with 24 gauge solid silver.. my guess is that those who find bass to be weak with silver may just be using cables that have smaller diameter conductors. This can be the case since silver is more expensive and has slightly better conductive properties, so cable companies could be using thinner wires to make the cables, reasoning that the better conductivity of silver will make up for a higher gauge relative to copper. But it doesn't.