do you need taste if you can massively parallel a/b test your way to something that is tasteful? say like you take your datacenter of geniuses and have a a rubin-loop supervising testing different directions. shouldn't that be close enough?

"taste" here is an intractable solution. Just take a look at how architecture has varied throughout the history of mankind, building materials, assembly, shape, flow, all of it boils down to taste. Some of it can be reduced to 'efficiency' -- like the 3 point system for designing kitchens, but even that is a matter of taste.

Find three professional chefs and they will give you three distinct visions for how a kitchen should be organized.

The same goes for any professional field, including software engineering.

Can infinite monkeys produce Shakespeare?

That approach leads you to products like instagram.