I would agree with most of what you are saying but on most exchanges there are not too many coins paired with anything but Bitcoin. Especially the newer the coin is the less likely there will be other pairings outside of bitcoin. Therefore you will have to go through Bitcoin in some fashion with the exception of a few pairings with ETH. Something like ADA or Ripple would need to be sold to Bitcoin just to be sold for LTC or ETH or whatever. If transaction fees are really a worry will they take that chance of double Bitcoin fees to move, for example, ADA to ETH? (ADA to Bitcoin fee and Bitcoin to ETH fee).