True in one regard, but this is not singular point either. For example, I have a huge box of take-out pickups here and many of them are Gibsons. They span from 490's, to ones that have no stickers, to the newer Gibson "slug" variants with 5 conductor wiring.
I can tell you this factually,
based on what I have here in my box.
There is not a single low DCR pickup (including Duncan Designed, a Carvin and a few genuine Seymour Duncans) that is louder on the VU meter than a higher DCR pickup.
Maybe such a thing is possible, and I do not discount that as a possibility, but I am yet to see it. I spoke to the guitar shop owner about this question last night and he agreed that he has yet to see a lower DCR pickup be louder than a higher DCR counterpart.
My Mom has two vintage Les Pauly's from the 1972-1979 era and both have the T-Top pickups in them. Both have the most beautiful clean tones you could ever hope to find in any guitar I have ever heard. But when overdriven, the output is noticeably lower and the gain structure is cleaner than most other guitars I am used to playing - and the volume output is lower than other guitars.
An example. We've tested the pickups for DCR on Mom's Les Pauls for the purposes of putting them up for sale. The bridge pickups are around 7.75k and the neck about 7.52k respectively. As I said, both sound BEAUTIFUL clean, but if I plug into my Origin and crank it up (which we did a few weeks ago after I picked it up from Greg) I would say that both Les Paul's have about 3 to 4 dial positions lower volume (on my Origin) than my Stratocaster with a 16.5k/44awg/A9 DiMarzio Neanderthal - which is exactly what I would expect.
I am constantly playing through vintage guitars on recordings and this theme is consistent among those instruments in terms of volume output.
But, TBTH, I think this lower volume output is exactly what draws people to these vintage guitars. and I believe the "cleaner" gain structure is another aspect of the siren's song - and that's totally cool.
I recently had a 1958 Les Paul here for repair. I actually had to notify my homeowner's insurance and send them a copy of the guitar's appraisal sheet because of it's value. The owner asked me to put a set of original PAF's into it as he received it with some very, very old Duncans. he came up with a set of Gibson PAF's from the era, complete with all provenance and I installed them.
He was very surprised (and pleased) that the guitar basically became "clean" after the PAF's were installed and when he played through his own personal amp (a Van Weelden) has was stunned at how his previous settings no longer produced any real gain to speak of.
But, again, this was expected when I installed pickups with far less DCR.
When DiMarzio cooked up my signature pickup, we ended up with a 16.5k DCR / 44awg / AlNico 9 magnet with a MV rating of around 450, for comparison purposes. I wasn't given resonant peaks, etc.
But I can tell you this about YelloStrat. If you set up an amp with your choice of guitar and dial up the gain where you want it, and then you plug in YellowStrat, you will have to turn the amp down 3-4 dial positions to get the volume level back to where it was with the other humbuckers. But, it never squeals, or exhibits other form of bad sonic behavior.