general tonearm design question

Many popular tonearms are designed with with the fulcrum for the vertical axis at ~70 degrees (e.g. Rega, SME), rather than perpendicular (e.g Origin Live).

Doesn't the former design cause the needle to track to the outer groove as the counter weight swings downward?

...or does the cartidge/tube somehow counter this?

Would a counter weight mounted at 90 degrees to the fulcrum, yet the arm tube set at 70 degrees be the solution to this, or am I wrong?

(The reason I started wondering about this was due to the varous Rega counter-weight mods. I would think that a lower center of gravity would exacerbate this problem. Furthermore, wouldn't a lower center of gravity only be effective on a uni-pivot design?)

your thoughts?