800vdc Data Center Power, Why Transformers Still Persist, Cost Less & Simple & Reliable even if Bulky & Heavy and Less Efficient

Efficiency does not always sell well. VW XL1 for $110K+ smaller than a Mazda Miata, able Diesel PHEV commuter only 250 units made, able to get 262 MPG or 1L per 100km, or Aptera with class leading low drag or aircraft like slippery aerodynamics. In a world of Utility, Comfort, SUV focus, new car buyers rarely place Efficiency at the top of the priority list, and in a world like that, coal power permits as do magnetic transformers, arc lighting, and other legacies like lead acid batteries, or diesel engines, even in face of Axial Flux motors in Range Extended Electric Vehicles.  

Higher voltage means smaller wires carry more power, and if we see into the AI training boom through 2035, we see more power efficiency focus, ammonia chillers to reduced HVAC costs, economies of scale custom ASIC solutions for specific workloads, Inference Models sell to companies and governments at every level generating substations profits unlike early LLM's and similar early AGI system, which have problems with hardware going out of date before model generates revenue, upside down tokenization cost per user input, burning cash without any profit generated. Clearly there must be light at the end of the ai training tunnel, on our way speeding towards ASI systems to tell us what we are looking for, answers to every problems or something, the so called technological singularity, spawning a singular machine entity with more intelligence than all brains biological in all of history on digital or quantum computing systems. 

Solid State Transformers once drew massive investments, but flopped since 2011, because legacy electromagnetic transformer so robust, so simple, and so reliable, like class 8 truck diesel engines, or burning coal to make steam to make electricity, sometimes legacy solutions even if not the latest tech, are so much cheaper and so much more reliable, even when the up and coming incumbent offering best in class energy efficiency, if its a electrical ballast that burns out 20X faster, than that T12 fluorescent with long life magnetic ballast might use a bit more power, but at a gas station it ends up costing 30X less because it goes 24/7 for 50 years, at low cost. 

The same can be said for MH, HPS, LPS, Short Arc Xenon, in some applications not even the best LED works, in very hot for example, halogen oven or incandescent oven bulbs made of glass, ceramic, metal and tungsten, can operate where an LED would melt and catch fire. Now opposite, LED bulbs in a fridge kept 38 F and cold off most of time, until door opened, that LED might last more than the life of the fridge.