It's still dirt cheap compared to credit card or paypal processing (something like mandatory $0.25 + 2% or more). Miners have to be paid with fees pretty soon, after the next halving, the mining reward from fees will be very important to keep miners on board.
pretty soon as in 2140?
I would say: yes reduce them. Prize has trippeled over the last month, on a similar level, Transaction fees should be lowered to 1/3 of the original value so the worth of the transaction fee stays the same. Miners will still get paid an equal amount in value so i don't see why that is an argument to not do it. similarly, if we reduce the transaction fee according to bitcoins worth, spam protection will stay the same, as the serious spammer will still have to invest the same amount of value to spam.
By not reducing the minimum fee we are slowly taking away one of the advantages of bitcoin.
No, pretty soon as in next halving. 1800 BTC per day production isn't going to keep enough miners interested, but the fees will. if you want security, you pay the fee. Better security increases the value of your own BTC.