Bitshares charges very, very small (think dust) transaction fees and puts them into a reserve pool that is used to fund maintenance and development. Because Bitshares has one of the highest transaction volumes in the world (many days higher than Ether and Bitcoin combined) the reserve fund is now worth over $100,000,000 USD. Bitshares is a sustainable, autonomous, self-funding block chain business.

Steem charges no fees and currently is being maintained and developed by a centralized corporation (Hello, Ned). If the corp goes away, so does Steemit. If the corp stops maintaining and developing, bye bye Steemit. If the corp runs out of money... well, you get the point.

Free transactions are nice while they last, but nothing is life is free. Bitshares is an autonomous company that generates revenue and pays for it's own maintenance. Let that sink in for a minute. :)