They can and do. I come from a background in micro-vibration and it's effect on opto-mechanical devices, but the same issues apply to electro mechanical devices. This type of isolation is widely used in many indistries for the same reasons.
Spikes in audio applications are used for "Mechanical Grounding". This both allows a path for spurious vibrations to follow (they drain away from the component in question and dissipate as heat - the ever reducing cross section serving as a waveguide), as well as providing a reduced contact point on the surface that the component is mated to, thus preventing the translation of any of that surfaces vibrations being transmitted back into the component. A very effective and cheap tweak, especially when combined with mass loading.
Regarding the construction as well as the pricing question asked in another thread, the construction of the spikes allows you to couple them tightly to the base of your speaker and still be able to adjust the height of the spike, and thus allow for changes in the tilt of your speaker. We all know what effect rake angle has on our Martin Logans, and how minute adjustments of same can effect imaging and soundstage. The $50.00 price is for a 2 pack of the spikes, with a $150 adder for an 8 pack, or a $100 adder for a 6 pack, Thus, if you have speakers that require 4 feet per speaker (Summits, Vista etc) it will cost you a total of $200 for both speakers, and if you have a 3 foot setup (ReQuests, SL3's etc. ) it will cost you $150 total for both speakers. Considering the construction and the fact that there are multiple machined components required to make them, the price doesn't seem too far out of line.
