A Zeiss lens superior to a cheaper Japanese variant? Probably, but is it $1000 superior? I guess that's subjective. Leica lenses have really amazing performance, and I think they are probably worth it assuming you can afford them from what I've seen (I personally cannot afford them).
I'll be the first person to say that a Zeiss or Leica lens is not necessarily better in any way, than some Japanese lenses. The 50mm f/1.4 Super-Multi-Coated Takumar being one of the main examples. The Japanese lenses are often found in better condition and had the best coatings in the world once SMC was introduced. If I only had a Pentax Spotmatic with 50mm SMC Takumar, I would have nothing to complain about. There is too much lore about Zeiss and Leica. Back in 2012, I put a Helios 103 against a 50mm Summilux ASPH that had just returned from Leica. The Helios only fell short in the corners at wide apertures, other than that, it held up against the Leica optic, shot for shot, aperture for aperture, aat and above f/2.8. I've gone down that road and found, after owning and using tens of thousands of dollars in equipment, that Nikon and Pentax make the best images, for the most part,
in my opinion. There are some things that lens design force, such as retrofocal optics clearing reflex mirrors. These optics add at least 2 air/glass surfaces and introduce more aberrations and distortion. This is why a $20 Jupiter-12 which is
properly adjusted can beat a brand new SLR lens such as an equivalent Canon or Nikkor 35mm f/2. The same goes for medium format optics, which can be quite compact, as long as the rear element doesn't have to compete for space with a reflex mirror. This is how and why TLRs can be as compact as they are and give such good images as they do.
I love Rolleiflex TLRs and I wish I still had mine but I'm perfectly happy with my Yashica D, which cost me lust a little less than the CLA on my old Rolleiflex 3.5E did.
When I say "cheap" I mean things like leaf shutter SLRs and post 1970s FSU cameras. They all need work and sometimes 50+ years has not treated the camera insides as well as the outside. Those Vito versions always look gorgeous on the outside and have bright finders, but they are incredibly complex and clumsy to use reliably, for long.
I thought I was going to get a Canon P for my first interchangeable lens rangefinder but it wound up being a Leica M2 because a friend made me a deal on the camera. Looking back, I wish I never sold my original Hexar to fund the M2.
Going back to TLRs and cheap vs not, I really want a Koniflex now. After all this time, I've "collected" all the gear I could ever want and more than I need, but I still want that Koniflex with a Heliar lens copy. It makes gorgeous images and it's Konishiroku, so that's enoug for me. One day, when I have a spare $400 to blow. Really, if you want a good medium format shooter, for not much money, you can't go wrong with a Yashica-Mat or Yashica D/635, Minolta Autocord, or Ricoh Diacord. The key to making sure they work is to get them serviced by a knowledgeable tech, that's why all those Autocord focus levers are broken, because people are forcing them against 60 years of hardened helical grease. They all used lenses almost identical to most Rolleiflex models (except for the Planar lens models), in that they use a Tessar design. Any one of them will do just fine and make great images, as long as they are serviced. Heck, purchase any cheap camera and have it serviced, and you're still in for ~$200, just because the technician's time. But it is very worth it to have a camera which is properly working, not just a kludge fix that will eventually need servicing.
If you have Retinas, go shoot them!
Phil Forrest