I remember when Microsoft first attempted to prevent the standardisation of Open Document Format (used by LibreOffice and others) and then bullied its way into getting approval for own OOXML standard. Already back then, supporters of FOSS warned that Microsoft would use the overly complicated OOXML to maintain its stranglehold on users of Office-like software.:
Whenever applicable and possible, standards should build upon previous standardisation efforts and not depend on proprietary, vendor-specific technologies. Albeit, MS-OOXML neglects various standards and uses its own vendor-specific formats instead. This puts a substantial burden on all vendors to fully implement MS-OOXML. It seems questionable how any third party could ever implement them equally well, especially when a standard comes with 6000 pages of specifications without serving its minimalistic purpose.
Yeah, you can put horses on any pasture and they will happily graze on whatever weed grows there. Gryphons (just one example of a popular fantasy mount) should be carnivorous. So how many cows do you need to feed that thing before it will fly someone safely across the countryside, without deciding that this someone looks awfully tasty?
Big flying mounts should be horribly expensive to maintain. Only the most wealthy nobles and wizards who can literally conjure money should be able to pay for them.
Personally I always have to suspend a lot of my disbelief whenever dragon mounts are being mentioned in fantasy books and there is absolutely no explanations how these creatures are being fed. Usually the topic is quietly sidelined or simply dismissed with "something something magic".