You have a very odd definition of "inflation." Unless you meant the economy was massively inflated back on live? I'd agree with that premise at least - a single purple enhancement back on live could cost as much as an entire build costs now, and I routinely sold certain PvP IOs off the market for 3-4 billion inf each.
Inflation hasn't been happening here because The Powers That Be have been careful to curb it as they find it practical - reduced merit costs, seeded salvage and super packs, bucketing, removal of double inf while exemplared, P2W vendors, etc. AH fees are a small part of it and while they may not do much on their own to keep the market reasonable they do work together with the other means of curbing it.