SLRs didn't have leaf shutters in the film days either. There's a few reasons for that. Firstly leaf shutters tend not to allow high shutter speeds unless you want massive vignetting, generally ...
Even though SLR cameras adopted digital image sensors as far back as the 1980s, other key components have remained defiantly mechanical. Mirrorless cameras removed the mirror and optical viewfinder ...
Leaf-shutter lenses exist for flash use on focal-plane-shutter medium-format SLRs, with shutter speeds up to 1/1600s @ f/2.8; so they'd be possible for small-format cameras - possibly with full TTL ...