chaadster

It's a complex dynamic, and while I believe what you say as a general rule, I think there are exceptions.

First, all tread is not equal. Some is characterized by tall blocks or deep grooves (as with the Marathon above) which reduces the surface area of the contact patch, while other tread designs, like a light file such as found on a Panaracer GravelKing, If they do at all, do so minimally, as the very low blocks of soft rubber deform under rider weight.

On an extremely smooth, dry surface where contact and available friction are at 100% of capacity, you want as much tread on the ground as possible. However, on a less than perfectly flat road surface, where there are small depressions (perfectly expressed in the case of asphalt surfaces), a smooth tread may not deform into those spaces, effectively reducing the surface area available for traction.

Now, take that imperfectly smooth surface and wet it, and you've reduce the available amount of traction-generating friction even more. A fine textured tread can deform into those depressions and crevices, regaining some surface contact and, therefore grip, otherwise lost to a smooth tread. Likewise, a heavily textured tread which does not deform into (or conform to) the small crevices of the wer roadway will only further suffer lower traction than a smooth tread.

Of course, the degree to which this matters or may be be noticable is highly variable on many conditions including rubber compound, tread design, tire size, inflation pressure, road surface, road condition, speed, etc. If one never goes out and pushes cornering limits in the wet, nor needs to do hard stops in the wet, then probably maximum wet traction is not an issue.