I wonder if that is more a commentary on a "cheap manufacturer" rather than the 1911 design.
I suppose you could make it into a commentary on cheap manufacturers, but I'm just going on record as saying the design is flawed in that it requires more expensive manufacturing processes to achieve the same objective as other proven, less expensive designs. Therefore, "cheap manufacturers" can't do it well, because even the cheapest version which works consistently well will cost far more than a pistol of similar quality but different design.
Now the implication/assumption is that the Glock has a higher tolerance for spec-slop or as you call it "robustness." But since there are no 3rd-party manufacturers of Glocks, this spec-slop "robustness" is complete conjecture. For all we know, each part of a Glock is hand shaped and fitted. Until a Glock is manufactured by anyone other than Glock, I think this particular criticism may not be applicable.
We know that Glocks are not hand shaped or fitted. We know that because of the lower price (and because if they were, you can bet it would be on their marketing materials!). We also know that because it doesn't take a trained gunsmith to install an extractor, nor does it require "tuning" as does a 1911 extractor.
Besides, many folks consider the XD and M&P pistols to be copies of a Glock. They do use many of the cheaper design/manufacturing methods I mentioned - yet they don't require the hand fitting and tuning required of a 1911.
Let's look at the extractor in particular. The 1911 extractor is a single piece of metal, long and elegant in appearance. It must be precise in several dimensions. The claw must have a certain shape, the pad must be the right height above the bottom of the claw, the claw recess must be curved just so, the extractor must be bent just right to maintain the correct tension, and must be tempered just right to avoid chipping or losing its tension. Any of these dimensions could be off by a tiny amount (the thickness of the pad being off by 0.001 inch could cause extraction problems, etc.) and the gun malfunctions.
Consider for a moment the Glock extractor. It's a single piece of metal with a single function - it grabs the case. It does not have to flex, which gives the heat treating much more latitude. It has a spring to push on it to give it the correct tension - and coil springs are very predictable and reliable. It doesn't matter if the Glock extractor is a bit softer or harder, or a tad longer or shorter, a bit wobbly or tight. It's gonna work.
I hope that explanation makes more sense to you. I love in-depth technical discussions.
NP - how do you feel about that as it relates to the LDA variation of the 1911? I do not have one personally but have craved one for a long time.
I don't know. Never seen one. I have heard that the trigger mechanisms (one of the more robust parts of a 1911) are much more delicate. Keep in mind, I'm not a gunsmith, nor am I an expert on the 1911. I am, however, a mechanical engineer.