What if these insufficient transaction fees causes miners to accept only higher fees, and this encourages miners to only accept even higher fees. Because of these high fees, people stop transacting.
Perhaps the only way to compensate is inflation?
I personally think the only mistakes of the original bitcoin design (if it really was originally designed to be a currency) was not instituting a fixed target of 2% inflation - a nominal amount ensuring things today will be cheaper than they will be tommorrow -- forcing bitcoin users to lean toward spending & investing but not hoarding.
It is for this reason I expect the CFTC to classify bitcoin to be a commodity similar to gold and not a currency like the dollar/euro/yen.