Was subpixel AA even ever enabled on retina Macs?
Yes, it was on by default, including on Retina displays. I just reconfirmed this using the Digital Color Meter to inspect black text on my 2014 Retina MBP running High Sierra.
More specifically, you could
toggle it on or off by selecting or deselecting Font Smoothing. And Font Smoothing was on by default. The caveat is that Apple also had a default cutoff of, IIRC, about 6 points, below which AA would not be implemented. That cutoff was, however, user-adjustable. See also:
How will Font Rasterization and Sub pixel rendering be affected with the new retina displays?
graphicdesign.stackexchange.com
The thing is, Apple could have continued to use subpixel AA on low-res screens and disable it on retina screens, just like they did for years.
But that's not what they did. Like I said, it was on by default even on Retina displays.
But of course, I perfectly understand that people can use displays differently. But if one wants to have a larger display to fi more content on it, you will need higher pixel density anyway.
No, you just need to have the same pixel density.
It is entirely unreasonable to expect higher image quality on a low-DPI display, regardless any AA tricks. Then again, I digress. This very discussion makes it clear that Apple doesn't cater to all the user's circumstances. Again, a business decision that one can view differently.
The position you're arguing against is never one I advocated--it's a straw man. It gets tiresome to have to keep repeating this, but let's try it one last time:
First, let's define some terms: Low-res is ~90-110 pi. Mid-res is ~160 ppi (e.g., 27" 4k). High-res is Retina (~220 ppi). [You may consider 160 ppi high res, but the distinction is important here.] Proceeding:
1)
I never advocated subpixel AA as a way to get sharp text on low-res screens. Instead, I advocated it as a way to get sharp text on mid-res screens. So when Apple abandoned subpixel AA, they weren't abandoning support of customers using low-res screens (that happened after Snow Leopard, which was the last OS that made text on low-res screens look good). Rather, they were abandoning support of customers using mid-res screens.
Specifically, with subpixel AA, which theoretically increases the horizontal resolution by 3x (the actual increase is certainly less), you could have a 4k 27" whose text was comparable in sharpness to a 5k 27" without subpixel AA. I.e., what subpixel AA offered was a way for the customer to have that "Retina" text sharpness with a $500 commodity 27" 4k display. Now, without subpixel AA, those same customers are required to shell out ~$1500 to get the same quality of user experience. That's a big ask for a Mini or MBA customer who wants an external display.
They're not going to bring back subpixel AA so I think, given Apple's current OS's really need a Retina display to be properly experienced (that "curated" user experience), that they should, correspondingly, offer consumer-priced large Retina displays, which the ASD is not.
[Some background: in the 00's, I happily used a low-res screen with MacOS, up through Snow Leopard. But Apple changed its text rendering with the next OS (I don't know what the specific change was), which meant text no longer looked good on low-res screens, even with the subpixel AA. That was Apple's first key transition: For text to look good, low-res screens no longer worked, forcing the customer to upgrade to mid-res. [The actual cutoff for looking decent was ~130 ppi, since it looked OK with the 1680x1050 upgraded display option on my 2011 15.4" MBP, which was 129 ppi.] After I got a 4k 27", I was again happy on MacOS until the 2nd key transition, which happened after High Sierra. Then, with the loss of subpixel AA, mid-res screens no longer looked great, so you needed to upgrade to high-res.]
If a larger display has the same effective resolution as a smaller display, isn't it kind of obvious that it is supposed to be viewed from further away? I mean, there is also the size desk and the question of ergonomic etc. The numbers I quoted are recommended viewing distances for different types of screens.
You're a smart guy, so I don't know how you've gotten yourself so confused about what I've been saying, since I think I've been crystal-clear. When I say I use my 15" and 27" at the same distance, I'm referring to the 15" Retina on my MBP, and the 27" Retina on my iMac. These are
not the same resolution! The 27" is about twice as big, with the same ppi, so it has about twice the pixels in each direction. You're talking as if I were comparing a 15" Retina to a 27" HD, which I clearly wasn't.
Given I have about four times the screen area on my iMac as my MBP, but the same ppi, I can indeed display four times as much content on the iMac—but only if I keep the font sizes the same, which in turn requires I keep the reading distance the same. Do you understand?
I simply don't understand buying a 27" Retina external for your 15" MBP, but then moving it twice as far away, such that you can't display any more readable content on it than on your MBP—at least if you're trying to get work done (spreadsheets, calculations, coding, document prep). If you're just surfing the internet, OTOH, I suppose it doesn't really matter—but then you don't need a big display anyways.
Now the cool thing is that, with subpixel AA on my 27" 4k, I had nearly the sharpness I get with my 27" 5k currently. Which meant I could use the same viewing distance for the former as the latter, and thus display the same amount of content*, and thus have the same productivity. I.e., subpixel AA allowed me to use my $500 27" 4k as it if were a $1600 ASD (at least when it came to text; I expect the the ASD is better for photography and graphics).
[*More precisely, nearly the same; getting the high sharpness also requires running 2:1 scaling, which results in a bigger UI than on the 5k; but since, with my apps, the UI is only ~5-10% of the real estate, a 40% increase in UI size means only a 2-4% reduction in real estate.]
