By strict definition, I think every course is "built", because the greens, tee boxes, fairways, etc sure as hell aren't naturally occurring.
For this exercise, perhaps establish a ratio of found vs built to determine which category a course is placed in? For example, there is no doubt Kingsbarns or Chambers is in the build category, but for Pine Valley or Oakmont is there an approx % that could/should be used as a benchmark/cutoff?
Most of Sand Hills' greens are actually found and only micro-shaped; same for a lot of them at Dismal River and St Andrews Beach.
Generally, though, my definition of minimalism is that we have to shape greens and bunkers, but I'm trying to limit earthmoving or extensive shaping in fairways to maybe a couple of spots, the way everyone used to in the Golden Age, and, honestly, right up until Pete Dye. The earthmoving Pete did at Crooked Stick raised the bar, although not really because not many people recognized what he'd done there.
If you use that standard, then you're pretty much going to say everything before 1970 is "found", and everything after 1970 [except by a few favored architects] is "built", and how does that promote discussion?
I was trying to tease out which projects were pushing the limits for their day and age. Yale and Banff and Lido, everyone knows about, but most people don't recognize that Pine Valley and Oakmont were daring for their day.
Today, it's pushing the limits to NOT do that kind of stuff.