Bitcoin promoters say that transaction fees is nill or negligible ..i guess getting atransaction through will be costly if it is already not.
this is why the blocksize
but this is a more complex story/"problem": https://en.bitcoin.it/wiki/Block_size_limit_controversy
the thing is: once this is resolved and the blocksize increased (+ yearly increasion rate set) the future scalability of bitcoin is not in danger anymore. too bad some turned this into a "political" debate. i personally think that +90 % or maybe +95% of the users would vote for BIP 101 if they all understood BTC proper. But it don't matter what users want. It matters what the majority of the generating network (miners) accepts/wants.