I think it's important to be aware of the distinctions between consumables (and non-consumables that aren't even comparable) that jobs use. Jug pets and pet food items are (unfortunately) an absolute requirement for beastmasters at this stage of the game, so making them difficult to synthesise is just absurd. Ninjutsu tools are a good parallel, and no-one will argue that shihei are difficult to make or farm/acquire materials for. It's like any other system of mandatory consumables - you should have the option to craft them yourself or buy them. For newer pets this isn't possible. Phogg mentions that his wife levelled cooking specifically for Beastmaster - if that was practical all the way to level 75, it's insane for it to all change now.
Almost all existing jug pets and pet food items are relatively practical to make using materials that aren't that hard to acquire at the level that you'd be using them - at level 75 we even had CourierCarrie which you could make absurdly cheaply. Requiring level 100 fishing and an Ebisu fishing rod, or a readily available supply of dragon meat, is undeniably a new level and it's completely impractical with regards to creating your own consumables.
In my opinion, this is just another one of those things that SE makes pointlessly irritating or refuses to fix for no good reason. Jug pets could be modified to work across zonelines years ago. I don't think we've ever been given a good reason why all pets disappear when a Confrontation status is applied in eg. Voidwatch. Charm could easily have been fixed creatively; something as simple as bringing a charmed pet to within 0-2 levels of your own when Run Wild is used, for example. It just takes a bit of thought, and an understanding of how things work in practice. Regrettably this seems to be something that SE isn't keen to demonstrate.