The average merchant doesn't have magic items in my campaigns, other than consumables. Magic items however can still be purchased, ordered from, or traded with certain powerful organizations or beings (for services or for coin). Temples, arcane magistrates, thieves' guilds, dukes, viziers, shahrazads, witch covens, fey queens, sorcerer ghosts, dracoliches, and all manner of other powerful beings and organizations are out there, open for a trade of some sort.