>>4119641However, most people don't shoot fast zooms. What about primes? Well you see, small DSLR primes are optically inferior to these larger lenses. I'm sure your ancient FA 50mm f1.4 is smaller but it's also worse. Even the last remaining DSLR company agrees, so they made a big prime. This is not about the body design. It's about physics.
Because lens design is constrained by physics.
Mirrorless is mostly about being open to telecentric lenses, significantly better AF, and live histogram display. Not size.