Is tonearm bias a compromise, maybe a myth?

Amount of AS is necessarily a compromise, but with a pivot type arm there's going to be skating. Amount of skating depends on more than just VTF. It increases with stylus velocity and steeper offset angle. It is caused by offset angle - the plane of the cantilever is extended off to the side, rather than aimed at the pivot as in a linear type arm.
So set your AS for "normal" loudness of most of your listening fare, not highest velocity on a test record. Offset increases as the stylus nears the center of record. Too little AS could add to inner groove distortion. Amount of AS is a compromise, but not a myth. Channel imbalance is readily seen on a scope or with newer software available. Carts with long cantilevers - skating can be observed visually if viewed from directly in front of cart while playing. Either the cantilever is almost centered relative to the body, or it's off to one side or the other.

Quite a few romantic and interesting views of AS, carts, and arms here, but they are quite confusing and some, just plain wrong. Virtually all carts, both MM and MC with a conventional cantilever, have a rubber suspension damper. This is for obvious reasons and to control high frequency response. The natural HF rise is controlled by damping. This trades off imaging/phase linearity for FR, but it's a necessary compromise and prevents ear bleed and excessive cantilever excursion.

Carts are not preloaded with cantilevers to the left(?). Perhaps this can be verified with a cart designer like VdH or J Carr. Cantilevers should be close to centered when at rest. If your cart came with the cantilever SLIGHTLY off-centered, you can align to the cantilever rather than the body. A linear arm exhibits no skating because there is no offset. The stylus/cantilever should be free to track in either direction. there is no pre-canting.

Yes, AS is applied to the arm near the bearing, while skating occurs at the stylus. But it's the arm mounting and its offset that causes skating. That is the relationship between the plane of the cantilever and that of the stylus to bearing. Just because groove velocity and arm position have an affect on skating, doesn't change the basic cause or solution.

AS force has the affect of reducing VTF, slightly. This could have something to do with perceived SQ degradation. I haven't experienced this. A minimal value of AS would tend to center the image and balance the channels. If you don't have a scope or appropriate software, a tape deck with a good display will show this. Just because optimal value of AS is a compromise, doesn't mean you should throw the baby out with the bath water. My 2 cents anyway.