My understanding is that in the 70's and 80's Thorens tended to target the larger Hi-Fi Superstore outlets though some smaller dealers did stock them. This shows up in advertisements from dealers in the magazines so it does not surprise me if they were rarely demoed against the LP12.
Some of the components used in the AR XA (1960) were patented. I have not read the patent but it apparently addressed the suspension. The Thorens TD150 was introduced in 1965 and I have read but not been able to confirm that it was under license to AR. The T Bar sub chassis in the TD150 is reversed compared to the AR XA and with different platter dimensions and an arm board so was a very different deck to the XA.
The prototype turntable developed by Ivor Tiefenbrun in 1969/70 was based on the TD150. Ivor had once owned and then sold a TD150 and couldn't get on with the deck that replaced it so decided to develop his own version using parts machined in his Fathers factory. The Ariston RD11 was based on this prototype after Hamish Robertson got involved in 1970.
In my TT collection I have a couple of XA's along with a TD150 mk2, an early twin button Castle built RD11 as well as a couple of LP12s so am familiar with them all and over the last few years have been researching the history.
It is worth mentioning that despite the OPs desire to paint Linn as the bad guys that during the 70's and early 80's they were one of the companies that did not try to place restrictions on magazine reviews and I applaud them for that. See this article from Martin Colloms from July 85.
https://postimg.cc/jC4kwY6w