In the real world, token costs seem to be going up, as early stage pricing at a loss gives way to pricing that generates revenue.
Compute costs might go down a little over the next five years, but there's nothing coming along in hardware that leads to huge reductions in price. NVidia says don't expect better price/performance before 2030.
The models keep getting bigger, and people put loops around them which iterate, burning tokens.
Where is this cost reduction coming from?