My experience is to date, that Rega were instrumental in being responsible for the the commonly seen Tonearm Designs to date.
Rega as a fledgling Company had little if any protection for their IP.
This lack of protection and the response of the media to the Rega Products led to a spate of Copycat design and aftermarket modifications becoming seen in the market place for the Rega Design Tonearm and Geometry.
In a nutshell a very cheap Rega Tonearm was unashamedly being reported on in the mainstream media, as trouncing Established Brands Products.
The individuals who lurk with intentions, especially as Carpet Baggers, seeking out opportunist ventures, were very quick to offer their blingy wares under the guise of Upgrades.
Some of these Opportunists have become quite successful in creating healthy revenues, where they have taken the affair to the place where they are now competitors to Rega. Using Rega Design and Geometries to produce a Tonearm with its own Brand name and being a Market Competitor.
Then there are the Established Tonearm Brands not doing so well out of Rega being a competitor, sales are down, Olden Designs are frowned upon by the mainstream media.
Where does the established Brand go from here.
How about a one piece casting for a Straight Wand, with the Headshell formed in the casting, obviously this is pure cutting edge innovation not heard of previously 😂🤣.
How about a selection of a Material, that is not used by Rega and a few changes to the Geometry, very Bespoke and Unique 😆.
"Viola", and an Arm is produced that Rega has not influenced in any way, well the notion of it is never to be mentioned anyway 🤐 .
Most importantly, the 'J' or 'S' Wand is no longer king.
SME, Linn and others all adopted straight cast wands with Headshell formed in the casting.
I moved approx' 30 Years past, from the SME 3009, to a Linn Cast Wand Design and then to a SME IV with the Single Cast Magnesium Wand design.
Prior to selecting the SME IV, I was able to be demo'd the IV and V side by side, where the V was not an arm that was seemingly advanced during the demo'. I have also been demo'd the SME V on many occasion since and have not felt something extra special is in use.
I have heard a selection of variants of the Rega Design Tonearm both modified and New Brands versions. I have even bought into another Model produced by one of the earlier referred to Carpet Bagger Companies.
I have learnt from these encounters, the designs are all much of a muchness in how the end Sound is influenced by the Design or Geometry.
Most encountered have all been very similar and I will claim usually it is easy to detect that there is a unique trait able to be perceived.
Once this trait is discovered and a different trait is heard that is seemingly the antithesis to the Rega Design trait, for myself there is no returning to a TA with a Rega Design/ Variant of Design or Geometry / Variant of Geometry.
The unique trait being the music being produced is able to be perceived as being constrained, inhibited.
The TA with Rega design/geometry is not able to present as a design that creates the perception of having an unabandoned freedom and being with no inhibition or the worse very very little.
Think ? Woodstock with the Venue being the Madison Square Garden Arena or Woodstock at the Max Yasgurs Farm, where would one like to experience their Woodstock.
My own TA of choice today, and only as a result of the design choices made for it, is something leaning much more towards that from Max Yasgur's Farm Woodstock, there is without doubt, freedom of expression present and this is perceived in bounds.
My Plagiarised Rega Design TA's are on the Subs Bench or boxed and Shelved, only getting a small dosage of replay time, usually to demo' to others differences in the presentations between the similar designs and the alternate design in use.
Note: Many of my evaluations have been done with same TT on a same Support Structure and System, but not all comparisons have been able to include the same Cart'.
Note: A Rega Design TA will replay music just fine and recent experiences of the Origin Live TA's with a Sumiko Pearwood Cart' has left me quite impressed, but during the demo' of a certain model, there is the perception of being constrained being detected and today for myself that is a detractor and is little different to knowing a Speaker Cabinet Colouration is impacting on the sound being produced, it is not a rattling ornament distraction in any way.