Hi Jon,
I think you're seeing a skewed sample on the Forums; people who are interested in the craft of timber framing are going to participate here and are perhaps more prone to using hand tools. As Director of the Guild for 11 years I got to know most of the companies out there and I would guess that 95% of them use chain or hollow chisel mortisers or CNC. One high end company and highly productive near me still prefers drills (Milwaukee Hole Hawgs). Works for them; go figure. By the way, when I use a Mafell mortiser I bore 5/8" deeper to get past the curve of the chain so there is no cleanup.