Some of you are dreaming and living in a Canon market dreamworld, I shall ask if I can get Hasselblads measurements of super telen and show them here
Fluorite has advantage and disadvantage and have been used 100years in different lenses in for example microscope, this is not a Canon concept or patent if any one thinks that. Synthetically-grown fluorite has done that larger surface/element can be produced. It is just a design choice whether to use fluorite or other ultra low dispersion material. Nikon claims that fluorite cracks more easily than glass, and is more susceptible to heat , and claim their ED glass performs as well. .
Canon was not the first to use fluorite in a lens, however they were the first to use
artificially grown fluorite in lenses (1960s). Canon was also the first to create an ultralow dispersion (UD) glass element for camera lenses (1970, identical to ED elements from Nikon ca. 1975), as well as the first to develop SuperUD elements (1990s, identical to SuperED from Nikon, same timeframe). Furthermore, Canon was the first, and only, company to develop viable diffractive optics using a diffraction grating lens (again, 1990s). Canon was the first to utilize
multiple large diameter fluorite lenses in an photography lens (2000s). I suspect Canon will be the first to develop viable particle dispersion diffractive optics (2010s?)
When it comes to glass, Canon has definitely been on the edge, and been the first to either develop or employ new optical technologies in their photographic lenses. Canon was a laughing stock for decades at their insistence that a diffraction grating could be used in a photographic lens to increase refraction while controlling dispersion better than any plain optical glass ever could...yet, despite strong arguments that viable diffractive optics were literally "impossible", they persisted, and are now the only company in the world with diffractive optics (a technology they seem to be developing in earnest, with more than half a dozen lens patents based on the technology produced over the last several years...makes me VERY curious what we might see from Canon in the next decade...a whole new era in photographic lenses?) I give a hell of a lot of credit to Canon for continually pushing the envelope when it comes to optics.
One concession to be made to Nikon is their development of a nanocoating, a superior coating to multicoating. Canon developed their own design which operates on the same principal with a different approach, a year later (mid 2000s...although I believe both approaches were based on a paper written by an independent about the technological applications of moth eye design a number of years earlier, not sure if I have a link.) Nikon's "Nano Crystal Coat" was a significant development, and improved overall lens transmission to around 99.95% from the mid 90% range or less, by avoiding reflection entirely (vs. multicoating, which simply aims to cancel out as much reflection as possible...thus still costing in overall transmission because light IS still reflected.) Canon SubWavelength Structure Coating (SWC) is similar and achieves the same 99.95% transmission ratio, but the initial development of the technique still goes to Nikon.
There is no question that fluorite is a softer material than optical glass. Fluorite elements are never used for the front or back elements of a lens due to their greater succeptibility to scratching. That does not diminish their superiority for dispersion control as inner lens elements, however. From what I've gathered from Canon's information on their artificially grown fluorite, it has a more uniform structure, lacking the impurities of natural fluorite, which improves its strength over what was probably used in lenses nearly 100 years ago. I know that the EF 500mm and 600mm f/4 L IS II lens is a favorite of bird and wildlife photographers, most of whom usually have to tromp through the wilderness to get to good wildlife and birding locations...always risking a trip and a fall (which does happen). I've seen photos of people who've had their cameras mauled and chewed on by bears...and the majority of the time, aside from some cosmetic horror, the equipment usually comes out functioning perfectly.
So I have little worry that a fluorite element would actually crack under normal usage, and for all other cases...well, if you don't have insurance on ten thousand dollar equipment,
you deserve whatever disaster becomes you. 
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