The idea of this thread, that how the tubes are joined is what matters, seems off base to me. Yes robots can tig weld very well. In some case they weld better than a person with limited skills.
I would contend that the joining of the tubes is just one small part of the equation. The tubes chosen, the geometry, the fit, the accuracy of the miters, the alignment are all as or even more important than how the tubes are stuck together.
Put another way..........a good welder/brazer isn't a framebuilder but a framebuilder is always a good welder/brazer.
One other tidbit to think of. When building a frame only a small percentage of the time is spent welding/brazing. A tig frame may take 8 hours to build and a lugged about twice that. In either case the joining of the tubes takes less than 10% of that total time. The rest of the time is spent doing stuff that is every bit as important (maybe more so) to the end outcome of the build.
I hope that makes sense.
Dave