In this hyper inflation phase of Covid recovery, irrigation is going through the roof, mostly material cost (including trucking)
As to design, the biggest culprits, if you will, are sprinkler spacing and water window, which used to be 8 hours, extended to 10, but now seems to be a max of six hours, even for the dozen or so hottest days of the year. Pumping a million gallons per night in 6 hours requires 2800 GPM or so, vs "the old days" when a pump station over 2,000 GPM was typical, with extended hours. All the mainline pipe sizes could be smaller, too. So, it adds up. I doubt you can find too many supers or irrigation designers comfortable with longer water windows now, because it seems to be standard, and you can defend standard when things go wrong.
The debate has gone on forever. Back in the 70's, the suppliers used to do "free design" to sell their product, and to keep systems less expensive, designed for watering every other fw, each night. The high end irrigation designers then (and now) designed to water every fw every night, again, which is necessary only a month per year max. Golfers didn't like one nine being wet and the other dry, or sometimes consecutive holes were on different schedules, etc. For that matter, picky golfers preferred more consistency from day to day, so supers started watering 0.1" per night rather than 0.2" every other night.
Soil moisture monitors in more common use now show that much turf doesn't need 100% of Evapotranspiration (the old way to measure water need) so there may be some hope, but not many in the biz want to chance some browning that might occur every summer with a smaller GPM system. If it happens, it will probably be due to govt. regulations, not those in the industry, for whom green is still the priority, as opposed to minimum water use (unless, of course, they are paying for it)