Late to this one but this is always an interesting topic for me as I come from a GC and cabinet/millwork/molding perspective and as Im sure many here did, went through the cusp of the break over into what is now called "home building".
Came up in the trades when everything went in unfinished. Case and base went up sanded and dead raw. Miters were sanded in in place, tight, clean, by the finish carpenter who made sure his miters and copes looked perfect before finish. Stain went on, got all over the walls and the subfloor, 2-3 coats of clear went on, all over the walls and subfloor, and then all subsequent trades installed with respect and to make their work meet the standard of the woodwork. Makes total sense.
You cant install prefinished trim without it looking like prefinished trim. You will have doctored up miters and joints that have been buttered up after the saw blade got a little age on it an the clear coat, or the clear and stain, splintered back to the bare wood and a field wipe of stain, clear, stain mixed with clear, or just a gob of putty, fixes the situation.
We installed all our cabinetry prior to flooring, and often times prior to finishing, so the finishers could come in and dress all the joints, make everything beautiful, flat and smooth, and fly on a finish that made the cabs and the trim look like it grew out of the walls. Of course even as late as the 80's you were talking about plastered walls that were floated in on grounds tacked to the jambs with darby's so your door openings were perfectly flat with no humps and bumps so your casing and base landed dead tight to the plaster and there was never a need to caulk, and your walls were smooth and as hard as glass. Now the only argument is that a factory applied finish is more durable which is not to be argued.
Then you moved through the 90s and into high end homes being finished with level 2 drywall, if you were lucky, level 3 or 4 if you were on a really nice job. Most jobs today have no idea what a level 5 finish is even suppose to look like forget about a rock solid top of the line skim coat veneer job over blue board. Youve got guys dumping a half a bottle of dishsoap in a bucket of compound in an attempt to drop the 3 gallons of compound they are going to sand off for every 5 they put on directly to the floor so they dont scatter dust around the whole job.
With the onset of low end drywall everywhere we moved to caulking in all our work with a tiny rad of caulk between all the casing, base, millwork, and drywall to try to accomodate the "surfs up" waves across narrow floated but joints, fat corners, hollow corners, and so on. All the while watching the HGTV, DIY, and home center world, smacking trim and cabs in with zero scribe, zero caulk, zero cutting your paint in. Its just blow and go. Gaps are just the norm.
Then we land in the disaster zone. You pre-paint all your trim on saw horses (forget about stain and natural finish because its too much work), you prime and two coat your walls before any of the trades to follow come in the job so that the finish painted walls get boffed, dented, smudged, destroyed, and at the end they pay a $10 an hour guy to go around and spackle and roller and brush touchup that will stick out like a sore thumb for the duration until the house is repainted. Or even better now we have "primer and paint in one" so the days of us scuffing plaster, prime, scuff again to denib, first coat, scuff again, and fly on a flawless second coat... your in the one flew over the cuckoo's nest world with that one.
You install all your tile and hardwood prior to any other work so you can be sloppy around the edges and not have to make nice cuts. Dont have to rake out your grout, and run a nice bead of color matched caulk that will come and go with the building over time leaving a nice cleanable, livable, moppable, joint at the base/tile connection. Instead you have to live with pre-finished base, dropped on top of tile, all of which has a rad and a recess at every grout joint, so now you have a nice little gap at every grout joint that in a single year will turn black with crap and crud growing out from under the base that unless a cleaning lady gets down on her hands and knees with a tooth brush will stay there forever. The base was likely only pre-finished on the face so its wicking up mop water in each of those grout gaps destroying the finish in 5-7 years.
Hardwood is no different. Walk into one of these new homes with heavily scraped, prefin, floating or staple down hardwood, and the base is dropped straight on top with 1/16" to 3/32" gaps at every valley in the scraped floor. Each of which will be filled with pet hair, grease, trash, lint, scrambled eggs, and ketchup, for the forseeable future. Not to mention how some marketeer managed to con a bunch of people into installing "hand scraped" flooring that creates massive valleys in the floor concentrating all the wear in the wafer thin engineered flooring to the .5% of the surface area that remains in the peaks. In a few years we will be tearing out miles of hand scraped flooring that the finish has broken off from because all the peaks broke through the finish but the valleys are completely in tact. Heck, carpet installers back in the day would float out a hump because that hump would
Now comes the real winner. The logic behind installing your flooring first is because its faster and saves money. How is burying perhaps 50-100' of flooring on an average large kitchen (20-30' of base cabs anda large island) saving any money at $15 a foot? It doesnt cost $750-$1500 to cut around cabs. There are cuts in every job. They cut around every obstacle in the job. Why would anyone roach a grand of flooring under boxes that will never be seen?
Its just plain lazy. But thats the world we operate in.