These early wheel sizes are no longer in production and are extremely rare, and the only alternative was a low-cost cast reproduction, which is typically heavier and weaker.
EB Motorsport’s version of the Porsche 911 FUCHS Wheel Deep 6 x 15 Plain Aluminium, is CNC machined using aerospace-grade aluminium, from the hub mounting to the front rim face, optimising the wall section, keeping material where strength is critical, and removing it where not. This produces a wheel that is inherently strong and almost as light as the original forged wheel.