dont know why.
as you leveled up and it cost more and some portals get 'unavailable' after i was gone for few months, as a dragon, i flew from chironic/drak to bristigo and it took me 15-20 mins, then got bored and logged out after i checked my dragon's money, i am broke from last time i was building my lair.
i guess i go back to hunting to make some serious golds since all those lair-making resources are shattered everywhere on istaria and need refining and crafting, but those hoverdisk need better weight limit raised, tired of putting 2 to 4 final crafted items to the lair out of several hundred raws each time.
cost of portals are "counter-productive"