It's really way too early to say. If bitcoin survives the next eight years it's probably going to survive forever. Once the mining reward drops down to an inconsequential amount, the price per coin goes through the roof and transaction fees skyrocket then Bitcoin has "made it".
Some people are
heavily disagreeing with that
On the other hand, the Bitcoin price can't go through the roof without widespread adoption of Bitcoin which is impossible without increasing the block size. And if we are really talking about exponential price growth (and, consequently, wild unrestrained adoption), the block size should evidently increase multifold. But greater blocks would allow to accommodate more transactions, so if the miners don't want to shoot themselves in the foot with the price shooting through the roof, they might want to lower the fees substantially since they will get more revenue through the fees if the number of transactions per block increases as well
I'll help you out with that other thread. Tell him the increase in transaction fees was "designed into" the system by the great and beloved Satoshi. Then quote the white paper to him. Tell him the concept was to "reward' (pay) miners to "secure" (because that's what mining really is) the system. Satoshi almighty realized that miners won't work for free and they certainly won't pay for (as Satoshi put it in the white paper) CPU time and electricity cost to mine at a loss. Transaction fees are "designed" into the system to eventually be a full replacement for block reward. That means fees need to be as high after each reward drop as the sum total of the loss in block reward + fees were before the reward drop. If he doesn't understand that then stop talking to him because he's an idiot and will never understand how Bitcoin works.
By convention, the first transaction in a block is a special transaction that starts a new coin owned by the creator of the block. This adds an incentive for nodes to support the network, and provides a way to initially distribute coins into circulation, since there is no central authority to issue them. The steady addition of a constant of amount of new coins is analogous to gold miners expending resources to add gold to circulation. In our case, it is CPU time and electricity that is expended.
The incentive can also be funded with transaction fees. If the output value of a transaction is less than its input value, the difference is a transaction fee that is added to the incentive value of the block containing the transaction. Once a predetermined number of coins have entered circulation, the incentive can transition entirely to transaction fees and be completely inflation free.
Oh, one other point to help your argument. As a miner long ago, I mined a ton of Bitcoin. When you mine the equipment you mine with gets really, really fucking HOT. I mean like fry a fucking egg hot. Computers and HOT go together like gasoline and a match. Mining equipment needs to be constantly upgraded and replaced as you mine (I bought dozens of HD 5970 GPUs as replacements when I was mining). As these farms continue to mine their equipment replacement cost will continue to go up at a rate equal with the annual cost of living increase. The transaction fee increases will also need to include the cost of mining equipment replacement. Any mining company (farm) that doesn't understand this will go out of business or have their profit dwindle down to nothing.