Why Linear Tracking never took off?

I got my first linear tracker, a Garrard Zero-100, in 1974. When I first saw their ad I thought they had the Holy Grail. After getting the machine, I wished dearly for 2 things: that it was manual operation from the ground up, and that they had spent the money on the articulation. The arm would not track for beans!

A year later I found a Rabco ST-7 mounted on a Technics 1100 table, so it was the world's first straight tracker (the Rabco was built in 1968) on the world's first direct-drive table.

I had the Rabco until about 1989. It got heavily modified- carbon fiber arm, a much-updated servo control that worked really well (the arm was famous for skipping or lifting off the LP due to servo malfunction- their original 'servo' was a joke), modified counterweight and modified track.

I replaced is with an SME V and was a lot happier... but I have often thought about how to sort out the arm's weaknesses since. There is a company called THK that makes motion tracks that have no bearing slop, that integrated with more modern bearing designs and an LED activated servo would result in a world-class arm.

IMO/IME none of the air-bearing arms work very well as often they have more tracking angle issues than a good radial tracking arm due to flex in the cantilever of the cartridge.

I am glad I had my Rabco when I did- it did very well on the inner 1/3 of the LP so my records from that time are intact.

I always wish someone can make a tonearm mounting system that allows you to install your pivot arm on it and then servo control its lateral movement, gliding one direction like the Rabco. Imagine a gliding armboard with your favorite pivot arm and then you can compare it to the fixed position in its typical pivot operation. Of course when operating tangentially, user has to neutralize the typical 23 degree offset angle at the headshell to zero degree. This will settle the argument against or for tangential servo arm. Manufacturers please take note. The THK system will work handily.

What if I put an armboard on top of a THK motion track and use the Rabco part for sensor and motorization. I bet that will work if look bulky. Just imagine a Rabco mounted upside down. A typical 9" pivot arm will work just fine. The whole thing won't be able to sit on top of typical turntable plinth and it will have to be next to the plinth as a separate arm pot. It should work for tables like Teres or ones with small plinths. So many projects, so little time......