Why are smoke odors persistent in fabrics?
Why is the smell of smoke so persistent, while many other strong smells are not?
In fact this is a tricky question, because you can't make such a comparison. According to IUPAC Gold book Smoke is:

An aerosol originating from combustion, thermal decomposition or
thermal evaporation. Its particles may be solid (magnesium oxide
smoke) or liquid (tobacco smoke).

So it is a fluid colloidal system in which the &quot;the dispersed phase is a solid, a liquid or a mixture of both and the continuous phase is a gas&quot; others strong smells that you smell during your every day life, are mainly already gasses. The interaction areosol-material an a gas-material is completely different.

Interaction between fabric and gasses
We can decompose the interaction in two different phenomena:

gas trapped inside the little voids inside your fabric
gas adsorbed in the fibers surface

The first is governed by Fick law of diffusion this process reach the equilibrium very quickly e.g. if you enter in a room with a gas after a couple of minutes the concentration of gas inside the voids of your fabric will be the same as the outside concentration.
The second is more hard to determine, however is more slower because the adsoprtion occur if there are free sites where the molecule can be placed, and this is a competitive process between all the others gasses present in larger quantities in the atmosphere, that already occupy these sites.
However if you stay a day in a room with a gas is possible the some gas molecule will be ad-sorbed in your fabric. This interaction is more persistent, however I think that the amount of substance is quite negligible.
So interaction between gasses and fabric is not very persistent.

Interaction between aerosol and fabric
This is completely different because colloidal suspensions are unstable. Aerosol are high energy system that tend to lower their energy forming bigger particles or bonds with other materials. So the deposition of these particles over the surface of others materials will be most of the times a spontaneous process. The high surface of the fabrics indeed make it easier.
So what happen when a particulates/aerosols settles on the fabric? This is not  gas trapped inside the little voids of your fabric or gas adsorbed in the fibers surface is a mixture of liquids and solids: many big (relatively!) &quot;clusters&quot; of molecules spread all over the fabric, from the tiny pores to the fiber's ravines. What matter here is the vapor pressure of the substance  you got this equilibrium (for a liquid):
$$\ce{Molecule_{(l)} &lt;=&gt; Molecule_{(g)} }$$ and the analogous with $_{s}$ instead of &quot;l&quot; for the sublimation. For both of these equilibria only the molecules in the liquid-gas or solid-gas interface can evaporate\sublimate, so the cluster surface is very important!

The case of Syringol

In the case of Syringol you have a solid that melt at 50–57 °C. So the sublimation is the only path that allows you to smell it. For most solids the vapor pressure is very low so the equilibrium will keep going to the right for a long long time, releasing syringol, until the source end.