Sony used to have a more straight-lined design in their cameras and very shallow grips. People didn't like that because the ergonomics are poor. That's why Sony

Sony used to have a more straight-lined design in their cameras and very shallow grips. People didn't like that because the ergonomics are poor. That's why Sony cameras started to look more and more like a Nikon or Canon in each generation. DSLRs are actually fatter than film SLRs because in a film SLR only the film plate and back are behind the focal plane, which are thin (~3-5mm), while DSLRs stack the sensor board, main board, display etc. behind the focal plane, so they got 15+ mm behind the focal plane. Mirrorless cameras with IBIS tend to increase the back-to-focal-plane distance further due to more involved cooling and IBIS.