ok let's say there is 10% spam. this means 1800 real transactions and 200 spam. the fees are now for example 0.00014514
so rich spammer paid for example 0.029 per block
after 2MB instantly there will still be 1800 real but 2200 spam. but spammer will pay only 0.029 again. this means the spam fee will drop to 0.000013195
So instantly after doubling the minimal fee for real users becomes very small.
Only after a while the real users will discover that fees are so small that they can send much more payments to some shitty services like satoshi dice. Basically some real users will become spammers.
If we could raise block to infinity fees would be zero forever because there is no point paying fees. This way we get infinite spam 1GB block = 1GB of spam etc.
instantly ?? um no..
after the 2mb triggers (a bit of time has passed for miners to finally desice to push forward eg 90% a safer bet to not risk orphans)
there would be 1800 real and 201 spam .. or 1801 real and 200 spam (1 transaction more while miners dip toe in the water)
later
there would be 1800 real and 202 spam .. or 1802 real and 200 spam (2 transaction more)
blah blah blah months, years later
there would be 1800 real and 2200 spam .. or 3800 real and 200 spam
sidenote: dipping toe in the water, inslow increments not only protects miners and allows them to access processing and propogation time of slightly larger blocks. and only add little more when they find its a safe risk that they wont end p being second place each time.. but it also keeps the demand there to still need a fee structure..
fee's should remain in the area of $0.001c - $0.05c at most.. just to keep bitcoins usefulness.. where the fee drops only due to bitcoins fiat valuation increasing..
going above 5cents is pissing off users because sending a transaction isnt cheap. and making it virtually free pisses people off due to spam.
i think the range of $0.001c - $0.05c seems to be a safe balance to keep everyone happy
if fee's are $0.000c the scenario would be more like 200 real and 3800 spam because its a spammers field-day and real users get pissed off
if fee's are $0.25c the scenario would be more like 200 real and 200 spam and 3600 buffer because both real users and pranksters wont find bitcoin cheap or useful