The major cities vandors only unlock once you unlock the other ones, so it doens't solve it, no.
My alt who's in SB has access to Kugane but where the tomes npc would be there's nobody yet.
I indeed also wish they would unlock them earlier, in ARR and HW you actually have access to them early on, it's more an SB and SHB think and I don't know why.

And yeah, I totally agree with raising the cap, it's way too low, both for that reason (saving for when you have access t the vendor instead of wasting), and because when you're "dumping" them it's easier to use mroe at once. I currently, on my main, use poetics to buy books I can raise ALC desynth with, but I can only get 3 every time I cap, so soemtimes I don't bother with the trip until dead moments and by then I'm capped.