In the future we will have generators that will _not generate_ until there is a certain amount of high fee blocks waiting, and then they will automaticity turn on their massive generation capacity and quickly generate the block. This leaves the average difficulty relatively low, and makes a strong incentive to include larger fees. These generators plainly wont include any low fee blocks, low fee blocks will have to wait around for a charity block.
How will the fees build up if the smaller generators are constantly processing them. there isn't going to be a sudden influx of high fee transactions... The large generators will simply be leaving all the profit to competitors. And if the competitors are snapping up any transaction no matter how small the fee, there is little incentive to pay a high fee in the first place.
There is a lot of guessing going in this thread, for we seem to have all fallen victim to the idea that we can guess the nature of a market that doesn't yet exist. As it is now, there is no incentive to pay a transaction fee at all, as the fee structure that currently exists is intended to limit spamming without prohibiting legitimately non-conforming transactions; not offer a profit motive to generators decades away. The fee structure can be altered without much difficulty on a technical level, but the future political issues are as difficult to predict as the market is. Yet many seem to get blinded by the profit motive as the
only motive for generation, which can easily be shown to not be the case presently, and I have seen no compelling reason as to why it must become the only reason in the future.