first of all people did not have the ability to choose between paying by address or paying by IP. it was always address based payment.
the confusion is this
the IP feature was not about payment destination inside a tx data.. it was about communicating with someone directly via their IP to get their bitcoin address from their node using a communication connection in the node. to then input the bitcoin address into a transaction.
secondly the fee was fixed at a low amount in the initial years. and it stepped down when there were halving cycles and a and large bitcoin market price changes..
people paying random amounts to outbid each other did not come about until much later
where the fee market game began
which is where the first fee wars started. where fees extended above a $0.20 range and have not really gone back down since.. even with years of promises that new features will bring fee's down, we have yet to see bitcoin (yes i speak of the bitcoin network and not other networks pretending to be bitcoin) offer fees below $0.20 for 8 years now
thirdly
a bitcoin block holds about 2500 tx per block on average. and there are about 144 blocks a day so theres normally atleast 360k transactions a day...
fourthly the fee back in 2010 was about 0.001-1btc which was at the time, the price of one whole bitcoin was ~$0.004, making the fee then not even 1cent because the price of a whole bitcoin back then was not even 1 cent and the fee was below 1btc