Why can't I hear 20 years of phono 'progress'??

How can this be??! A well-regarded 1980 Ortofon VMS20e MkII $150 mm cartridge in an ambivalently-regarded 1980 Thorens TD115 $430 turntable sounds identical to a highly-regarded 2002 Grado The Reference (high-output) $1200 cartridge in an equally-highly-regarded 2002 modded Rega Planar 25 $1275 turntable. Before you dismiss me as another naïve wacko, please read a little further.

I’ve been building a whole new system over the past year and a half, made critical auditions of dozens of components, and been quite satisfied with my 45yo ears and results. You can click on my system below for an OTT description, but with everything else in place, I’m listening to the carts through a fine BelCanto Phono1 -> AQ Emerald -> retubed Sonic Frontiers Line1 -> AQ Viper -> Steve McCormack-upgraded DNA0.5 -> AQ Bedrock -> Thiel 2.3 -> great room acoustics, or Headroom Max -> Stefan AudioArt Equinox -> Sennheiser HD600.

I’ve had the Rega-Grado paired for over two months, both items bought separately from A’gon. Cart has several hundred hours, P25 I installed the Expressimo counterweight, donut mat, snugged tonearm nut to plinth and set the speed to 33-1/3 with tape on the subplatter. FWIW, the Thorens has an upgraded mat and cables, record clamp and 10lbs of inert clay in the base, and new belts and styli over the years. The cartridges set up and align perfectly in both units, confirmed with test records. I know the 115/vms20 to be very synergistic, and, hum aside, had always thought the rb600/grado worked well together.

We’ve been just loving the sound of the Rega-Grado for those two months, so before I put the Thorens into storage I just wanted to remind myself what I had been listening to for 23 years.

That was a couple weeks and way too many hours of clinical listening ago. Despite swapping equipment stands, matching levels, and playing every type and quality of vinyl, I’ve never heard two pieces of equipment sound so identical, this after choosing between DACs, CD transports, digital and analog interconnects, vacuum tubes, headphone amps, preamps, etc.

Both the overall sit-back-and-relax musicality and every audiophile definition from general frequency balance and PRaT to bass articulation and depth retrieval are the same(!) The most I can say now is that on the best recordings with the most focused and careful listening, the P25 has more inner detail on vocals, more articulation on complex cymbal brushwork, and smoother massed strings. But most of the time I had to confirm this (barely) with headphones, it was below the resolution of the Thiels that have unraveled every other upstream difference before!

I’m sure a true Golden Ears with a $100K system could be more conclusive. The Thorens' semi-auto operation, sprung dustcover, detachable tonearm wands, replaceable styli, front-panel cueing, electronic speed control are all huge real-world advantages over the Rega-Grado hum, $800 retip and fully-manual operation. So what gives?? Have I done something blatantly wrong with the Rega? How can a 23yo $580 rig equal 5yo designs adding up to $2600? I always knew my 115/vms20 combo sounded good, but never expected this – I’d sell the P25/reference at a loss but for nobody believing that my archaic TT is even in the same sonic league! Plus the newer record player gives more 'street cred' to the whole system(?) All enlightened suggestions, useful comments and curious questions welcome. I've come to trust many of you and your inputs over the months, so don't be shy! No, I won’t be selling my Thorens at bluebook :-)