Mark,
I was going to answer that you had an engineering degree, but you took care of that for me! Glad to see you actually size pipe and basins by rational formula, rather than guess at 12" basins and 6" pipe like so many gca's........
I don't think modern gca's treat drainage that much differently than the old guys. Water still flows downhill. As TePaul suggests, when drainage was via concrete pipe, it was too expensive for golf course use. When the PVC drain pipes came out it changed the whole ball game.
The biggest influences in using more pipe, IMHO are
The cost, as above
Golf courses in floodplains used as detention basins (intentionally or not!)
Golf courses in housing projects, usually in valleys and taking a lot of nuisance water
Need to open quicker - I believe that long damp swales, often with turf washouts were acceptable in the days when golfers "knew" that courses took five years to mature. Now, we balk at five days after opening not being perfect.
Higher Maintenance Levels - While related to the above, we have found that if surface water travels more than 250' overland, it cuts a channel, or gets damp. For that quick opening, you need more catch basins or more sod, or both (sodding reduces grow in problems, but the long swales still stay damp under the sod)
Water quality requlations - by law we are supposed to direct surface water away from the creeks to filter areas. Environmental reggies now make us contradict nature.
And, the one that everyone seems to harp on here,
More extensive shaping for artistic effect - yes, its true that some architects some of the time are trying to replicate what Ross did at Pinehurst or attain some other dipsy doodle contours to enhance chipping, but without the benefit of sandy soils. Thus, catch basins become a necessity. And, since those areas work best near critical play areas (who is going to bump and run a chip from fifty yards left of a green?) many times those catch basins end up in high use areas.
JESII-
I would say nearly every course - Top 100 or not - has had continuous drainage work done. There is a saying in the super business - "you don't add drainage every year, just the years you work there"
I once sent some apprentices to Geoff Cornish's design class. He said that the typical drainage budget was $50K (old numbers) and my guys said we usually spent 3-4X that. Geoff's reply was that it probably totaled that after five years, so it was a new trend to just put as much as possible in up front, as the budget allows.
That makes sense to me, as does Mark's first point - never underestimate the need for drainage - is a good one that most amateur gca's and gca fans do not understand at all.